Broadcast service receiving method and broadcast service receiving apparatus

ABSTRACT

Provided is a broadcast service receiving method of a broadcast receiving device. The method includes: receiving an video stream among a content transmitted as a broadcast service; generating a request message for at least one of signalling information on the broadcast service and signalling information on an adjunct service of the broadcast service on the basis of part of the received video stream; transmitting the generated request message to a server through an internet network; receiving a response message corresponding to the request message from the server; obtaining at least one of the broadcast service corresponding to the video stream and the adjunct service of the broadcast service on the basis of the received response message; and providing the obtained broadcast service and adjunct service, wherein the request message comprises first query information for specifying a request time interval and second query information for specifying at least one signalling table to be requested.

TECHNICAL FIELD

The present disclosure relates to a method of receiving the broadcastservice and an apparatus for receiving broadcast service.

BACKGROUND ART

A digital television (DTV) is now presented to offer various services inaddition to a television (TV)'s original function such as playing videoand audio. For example, broadcasting information such as ElectronicProgram Guide (EPG) may be provided to a user, and also, broadcastingservices from at least two channels may be simultaneously provided to auser. Especially, since a receiving system of the DTV includes a largecapacity of a storage device, and is connected to a data communicationchannel and the internet (through which two-way communication isavailable), more services become accessible through broadcast signals.Additionally, since services offered through broadcast signals becomemore diversified, needs for utilizing the diversified servicesaccurately are increased and needs for providing broadcast informationsuch adjunct services to a user through an EPG are increased also.

DISCLOSURE OF THE INVENTION Technical Problem

Embodiments provide a method of receiving the broadcast service and anapparatus for receiving broadcast service, which effectively deliver anadjunct service for content.

Embodiments also provide a method of receiving the broadcast service andan apparatus for receiving broadcast service, which efficiently providea broadcast service through an internet network.

Embodiments also provide a method of receiving broadcast service and anapparatus for receiving broadcast service, which provide an improvedbroadcast service and its adjunct service without affecting a generalreceiver, and an adjunct service processing method of the apparatus.

Technical Solution

In one embodiment, provided is a broadcast service receiving method of abroadcast receiving device. The method includes: receiving an videostream among a content transmitted as a broadcast service; generating arequest message for at least one of signalling information on thebroadcast service and signalling information on an adjunct service ofthe broadcast service on the basis of part of the received video stream;transmitting the generated request message to a server through aninternet network; receiving a response message corresponding to therequest message from the server; obtaining at least one of the broadcastservice corresponding to the video stream and the adjunct service of thebroadcast service on the basis of the received response message; andproviding the obtained broadcast service and adjunct service, whereinthe request message comprises first query information for specifying arequest time interval and second query information for specifying atleast one signalling table to be requested.

In another embodiment, provided is a broadcast service providing methodof a broadcast receiving device. The method includes: receiving servicesignalling data of an adjunct service for a broadcast service; receivingan adjunct service on the basis of the received service signalling data;obtaining a guide object for the broadcast service and the adjunctservice from the received adjunct service; and displaying the guideobject, wherein the guide object includes a program guide and an NRTservice guide displayed in a partial area in an entire screen area andthe partial area is changed according to a state of the broadcastservice and the adjunct service.

In further another embodiment, a broadcast service receiving deviceincludes: an video stream receiving unit receiving an video stream amonga content transmitted as a broadcast service; a control unit generatinga request message for at least one of signalling information on thebroadcast service and signalling information on an adjunct service ofthe broadcast service on the basis of part of the received video stream;a network interface unit transmitting the generated request message to aserver through an internet network and receiving a response messagecorresponding to the request message from the server; wherein therequest message includes first query information for specifying arequest time interval and second query information for specifying atleast one signalling table to be requested; and the control unit obtainsat least one of the broadcast service corresponding to the video streamand an adjunct service of the broadcast service on the basis of thereceived response message.

In further another embodiment, a broadcast receiving device includes: areceiving unit receiving service signalling data of an adjunct servicefor a broadcast service and receiving an adjunct service on the basis ofthe received service signalling data; a service manager obtaining aguide object for the broadcast service and the adjunct service from thereceived adjunct service; and a display unit displaying the obtainedguide object, wherein the guide object includes a program guide and anNRT service guide displayed in a partial area in an entire screen areaof the display unit and the service manager changes the partial areaaccording to a state of the broadcast service and the adjunct service.

Advantageous Effects

According to an embodiment of the present invention, signalinginformation on broadcast service and adjunct service may be receivedefficiently and improved broadcast service may be provided by using anobject for adjunct service.

Additionally, according to an embodiment of the present invention, sinceeffective signaling tables are specified and received at a specific timetable, the load of a transmitting and receiving system and a network maybe reduced and an efficient broadcast service may be provided.

Furthermore, according to an embodiment of the present invention, byusing an XML and HTTP format, efficient service transmission through anIP network becomes possible.

Moreover, according to another embodiment of the present invention,since broadcast service and NRT service guides where a display area ischangeable according to a situation are provided, rich guide forbroadcast service and adjunct service may be provided to a user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram illustrating how RT service and NRTservice are provided.

FIG. 2 is a view illustrating a structure of NRT service according to anembodiment.

FIG. 3 is a view illustrating a protocol stack for NRT service accordingto an embodiment.

FIG. 4 is view illustrating one example of the protocol stack for mobileNRT service.

FIG. 5 is a view illustrating a bit stream section of a TVCT tablesection (VCT) according to an embodiment.

FIGS. 6 and 7 are views illustrating how to define a value of aservice_type field according to an embodiment.

FIG. 8 is view of data_service_table_section) for identifying anapplication of NRT service and bit stream syntax ofdata_service_table_bytes in a DST section.

FIG. 9 is a view illustrating a method of receiving and providing NRTservice in a receiving system by using ATSC A/90 standard fortransmitting data broadcasting stream and ATSC A/92 standard fortransmitting IP multicast stream.

FIGS. 10 and 11 are views illustrating a method of signaling a DSM-CCaddressable section data by using VCT according to another embodiment.

FIG. 11 is a view illustrating a method of signaling DSM-CC addressablesection data by using VCT according to another embodiment of the presentinvention.

FIGS. 12 and 13 are views illustrating a bit stream syntax of NSTaccording to an embodiment.

FIG. 14 is a view illustrating a bit stream syntax ofNRT_component_descriptor (MH_component_descriptor) according to anembodiment.

FIG. 15 is a view illustrating a bit stream syntax of NRT componentdescriptor including NRT_component_data according to an embodiment.

FIG. 16 is a view illustrating a bit stream syntax of NRT-IT section forsignaling NRT application according to an embodiment.

FIG. 17 is a view illustrating a syntax structure of bit stream for NRTsection (NRT_content_table_section) according to an embodiment.

FIG. 18 is a view illustrating a bit stream syntax structure of an SMTsession providing signaling information on NRT service data according toan embodiment.

FIG. 19 is a view illustrating an FDT schema for mapping a file andcontent_id according to an embodiment.

FIG. 20 is a view illustrating an FDT schema for mapping a file andcontent_id according to another embodiment.

FIG. 21 is a flowchart illustrating an operation of a receiver accordingto an embodiment.

FIGS. 22 and 23 are views illustrating a receiving system receiving,storing, and playing an NRT content for NRT service according to anotherembodiment.

FIG. 24 is a flowchart illustrating a method of a receiver to receiveand provide NRT service according to an embodiment.

FIG. 25 is a view illustrating a bit stream syntax of a triggeraccording to an embodiment.

FIG. 26 is a view illustrating a PES structure according to asynchronized data stream method including a trigger according to anembodiment.

FIG. 27 is a view illustrating a synchronized data packet structure ofPES payload for transmitting trigger as bit stream syntax according toan embodiment.

FIG. 28 is a view illustrating a content type descriptor structure intap( ) on DST according to an embodiment

FIG. 29 is a view illustrating a syntax of PMT and service identifierdescriptor according to an embodiment.

FIG. 30 is a view illustrating a trigger stream descriptor according toan embodiment.

FIG. 31 is a view of AIT according to an embodiment.

FIG. 32 is a view of STT according to an embodiment.

FIG. 33 is a block diagram illustrating a transmitter for transmittingTDO and a trigger according to an embodiment.

FIG. 34 is a block diagram illustrating a receiver for receiving TDO anda trigger according to an embodiment.

FIG. 35 is a flowchart illustrating a trigger transmitting methodaccording to an embodiment.

FIG. 36 is a flowchart illustrating an operation of a receiver 300according to an embodiment.

FIG. 37 is a flowchart illustrating a trigger receiving method by usinga trigger table according to an embodiment.

FIG. 38 is a flowchart illustrating an operation of a receiver whentrigger signaling information and trigger are transmitted using DSTaccording to an embodiment.

FIG. 39 is a flowchart illustrating an operation of a receiver when atrigger is transmitted using a trigger stream descriptor according to anembodiment.

FIG. 40 is a flowchart illustrating an operation of a receiver when atrigger is transmitted using a stream type according to an embodiment.

FIG. 41 is a flowchart illustrating an operation of a receiver when atrigger is transmitted using AIT according to an embodiment.

FIG. 42 is a flowchart illustrating an operation of a receiver when atrigger is transmitted using STT according to an embodiment.

FIG. 43 is a timing diagram according to an embodiment of the presentinvention.

FIG. 44 is a flowchart illustrating an activation trigger datatransmitting method according to an embodiment of the present invention.

FIG. 45 is a timing diagram according to another embodiment of thepresent invention.

FIG. 46 is a flowchart illustrating a maintenance triggering datatransmitting method according to an embodiment of the present invention.

FIG. 47 is a view illustrating a maintenance trigger receiving methodaccording to an embodiment of the present invention.

FIG. 48 is a timing diagram according to an embodiment of the presentinvention.

FIG. 49 is a flowchart illustrating a preparation trigger receivingmethod according to an embodiment of the present invention.

FIG. 50 is a flowchart illustrating a preparation trigger receivingmethod according to another embodiment of the present invention.

FIG. 51 is a view illustrating a bitstream syntax of a triggerconfigured according to another embodiment of the present invention.

FIG. 52 is a view illustrating a syntax of a content item descriptoraccording to an embodiment of the present invention.

FIG. 53 is a view illustrating a syntax of an internet locationdescriptor according to an embodiment of the present invention.

FIG. 54 is a flowchart illustrating a trigger transmitting methodaccording to another embodiment of the present invention.

FIG. 55 is a flowchart illustrating an operating method of a receiveraccording to an embodiment of the present invention.

FIG. 56 is a view illustrating a method of a receiver to recognizelocation information of a content item according to an embodiment of thepresent invention.

FIG. 57 is a TDO state transition diagram illustrating a method ofprocessing a trigger by a receiver according to an embodiment of thepresent invention.

FIG. 58 is a view illustrating a syntax of a link_descriptor accordingto an embodiment of the present invention.

FIGS. 59 and 60 are views illustrating contents of fields included in alink descriptor.

FIGS. 61 and 62 are views illustrating a linkage between each table whenthe link descriptor of FIG. 58 is included in a descriptor of an eventinformation table (EIT) among PSIP tables according to an embodiment ofthe present invention.

FIG. 63 is a view illustrating a syntax of an event descriptor(Event_descriptor) and contents of fields in the event descriptoraccording to an embodiment of the present invention.

FIG. 64 is a view illustrating a method of identifying a linkage programthrough an event descriptor according to an embodiment of the presentinvention.

FIG. 65 is a flowchart illustrating an operation of receiving by thereceiver 300 broadcast program or broadcast channel related contents byusing a link descriptor according to an embodiment of the presentinvention.

FIG. 66 is a flowchart illustrating an operation of providing by thereceiver 300 broadcast program related content by using an eventdescriptor according to an embodiment of the present invention.

FIG. 67 is a view illustrating a syntax of an NRT service descriptor(NRT_service_descriptor), that is, a service level descriptor accordingto an embodiment of the present invention.

FIG. 68 is a view illustrating a meaning according to each value of aconsumption_model field in an NRT service descriptor according to anembodiment of the present invention.

FIG. 69 is a flowchart illustrating an operation of the receiver 300when a TDO is transmitted by a TDO consumption model according to anembodiment of the present invention.

FIG. 70 is a flowchart illustrating a method of allocating and managinga TDO storage area according to a TDO consumption model according to anembodiment of the present invention.

FIG. 71 is a view illustrating a TDO metadata descriptor according to anembodiment of the present invention.

FIG. 71 is a flowchart illustrating an operation of receiving by thereceiver 300 TDO metadata according to an embodiment of the presentinvention.

FIG. 73 is a flowchart illustrating a method of the receiver 300 tomanage a TDO depending on time information in TDO metadata according toan embodiment of the present invention.

FIG. 74 is a flowchart illustrating a method of the receiver 300 tomanage a TDO depending on time information and priority information inTDO metadata according to another embodiment of the present invention.

FIG. 75 is a view illustrating a syntax of an internet locationdescriptor according to an embodiment of the present invention.

FIG. 76 is a flowchart illustrating an operation of the receiver 300when an FDT is transmitted through an internet network according to anembodiment of the present invention.

FIG. 77 is a flowchart illustrating an operation of the receiver 300when the URL of an FDT is transmitted through a link descriptoraccording to an embodiment of the present invention.

FIG. 78 is a flowchart illustrating an operation of the receiver 300when the URL of an FDT is transmitted through an NRT-IT according to anembodiment of the present invention.

FIG. 79 is a conceptual view illustrating an NRT service including anentry content item.

FIGS. 80 and 81 are views illustrating an NRT-IT to transmit informationon an entry content item according to an embodiment of the presentinvention.

FIG. 82 is a view illustrating an operation method of a receiver when anentry content item is transmitted according to an embodiment of thepresent invention.

FIG. 83 is a conceptual view of a plurality of NRT service objectstransmitted according to an embodiment of the present invention.

FIG. 84 is a view illustrating a syntax of an NRT service descriptorincluded in an SMT according to an embodiment of the present invention.

FIGS. 85 and 86 are views illustrating a syntax of another NRT-ITaccording to another embodiment of the present invention.

FIG. 87 is a view illustrating a syntax of an Other NRT locationdescriptor (Other_NRT_location_descriptor) according to anotherembodiment of the present invention.

FIG. 88 is a flowchart illustrating a method of receiving broadcastservice according to an embodiment of the present invention.

FIGS. 89 to 97 are views illustrating a network topology according to anembodiment of the present invention.

FIG. 98 is a view of a receiver 300 according to an embodiment of thepresent invention.

FIG. 99 is a view illustrating an XML format of a trigger according toan embodiment of the present invention.

FIGS. 100 and 101 are views illustrating an XML format of a Triggeraccording to another embodiment of the present invention.

FIG. 102 is a view illustrating a syntax of a trigger URL descriptoraccording to an embodiment of the present invention.

FIG. 103 is a view illustrating a syntax of a TDO trigger tableaccording to an embodiment of the present invention.

FIG. 104 is a view illustrating an operating method of the receiver 300according to an embodiment of the present invention.

FIG. 105 is a view illustrating an XML schema diagram of ACR-Resulttypecontaining a query result according to another embodiment of the presentinvention.

FIG. 106 is a flowchart illustrating a trigger requesting and receivingmethod of the receiver 300 according to an embodiment of the presentinvention.

FIG. 107 is a view illustrating an HTTP GET instruction format basedtrigger request message according to an embodiment of the presentinvention.

FIG. 108 is a view illustrating an HTTP POST command format basedtrigger request message according to an embodiment of the presentinvention.

FIGS. 109 and 110 are views illustrating an XML schema diagram of atrigger request result message according to an embodiment of the presentinvention.

FIG. 111 is a view illustrating a DO descriptor according to anembodiment of the present invention.

FIG. 112 is a view illustrating a bit stream syntax of a time slotdescriptor configured according to an embodiment of the presentinvention.

FIG. 113 is a view illustrating the contents of sub fields in a timeslot descriptor.

FIG. 114 is a view illustrating an application boundary descriptoraccording to an embodiment of the present invention.

FIG. 115 is a view illustrating a DO descriptor extended according toanother embodiment of the present invention.

FIG. 116 is a view illustrating an ILT according to an embodiment of thepresent invention.

FIG. 117 is a view illustrating a query table (Query terms for SignalingTable Requests) of a signalling table according to an embodiment of thepresent invention.

FIG. 118 is a view illustrating a timeline between a request and a replyduring Short Polling when a trigger is transmitted through internet.

FIG. 119 is a view illustrating a timeline between a request and aresponse during HTTP Streaming when a trigger is transmitted throughinternet.

FIG. 120 is a view illustrating a trigger structure according to anotherembodiment of the present invention.

FIG. 121 is a view illustrating a trigger stream descriptor according toan embodiment of the present invention.

FIG. 122 is a view illustrating a usage example of a trigger and a TDOAPI according to an embodiment of the present invention.

FIG. 123 is a view illustrating a Trigger stream association descriptoraccording to another embodiment of the present invention.

FIG. 124 is a view illustrating an ILT according to another embodimentof the present invention.

FIG. 125 is a view illustrating a URL function code value table used inan ILT according to another embodiment of the present invention.

FIGS. 126 and 127 are views illustrating a second query information andresponse relationship of a signalling table request message according toan embodiment of the present invention.

FIG. 128 is a view illustrating an ILT according to another embodimentof the present invention.

FIG. 129 is a view illustrating a URL_function_code value table used inFIG. 128.

FIG. 130 is a view illustrating a consumption model field including adata stream consumption model according to an embodiment of the presentinvention.

FIG. 131 is a flowchart illustrating a method of a receiver providingdata for a DO to receive broadcast service by receiving an NRT serviceallocated to a data stream consumption model.

FIG. 132 is a view illustrating an XML format of a multi-file HTTPstreaming request message according to an embodiment of the presentinvention.

FIG. 133 is a view illustrating an ILT syntax according to anotherembodiment of the present invention.

FIG. 134 is a table illustrating a URL function code used in the ILTshown in FIG. 133.

FIG. 135 is a view illustrating an XML format of a trigger API receivingreal-time data for a TDO according to an embodiment of the presentinvention.

FIG. 136 is a view illustrating a second query information tableaccording to another embodiment of the present invention.

FIG. 137 is a view illustrating a syntax of an adjunct EPG descriptoraccording to an embodiment of the present invention.

FIG. 138 is a view illustrating a syntax of an adjunct EPG descriptoraccording to another embodiment of the present invention.

FIG. 139 is a view illustrating a meaning according to each value of aconsumption_model field in an NRT service descriptor when an EPGconsumption model is allocated according to an embodiment of the presentinvention.

FIG. 140 is a flowchart illustrating a method of providing EPG on thebasis of an NRT service of an EPG consumption model, as a method ofreceiving broadcasting service according to an embodiment of the presentinvention.

FIG. 141 is a view illustrating a linkage between EPG and each tableaccording to an embodiment of the present invention.

FIG. 142 is a view illustrating an EPG provided according to anembodiment of the present invention.

FIGS. 143 and 144 are views illustrating an EPG screen when a userrequests additional information according to an embodiment of thepresent invention.

FIG. 145 is a view illustrating linkage information linked with othertables according to another embodiment of the present invention.

FIG. 146 is a view illustrating a syntax of a linkage descriptoraccording to an embodiment of the present invention.

FIG. 147 is a view illustrating a target type field of a linkagedescriptor according to an embodiment of the present invention.

FIG. 148 is a view illustrating a linkage descriptor according toanother embodiment of the present invention.

FIG. 149 is a view illustrating a DO operating in a partial area of ascreen according to an embodiment of the present invention.

FIG. 150 is a view illustrating partial areas where an EPG is to bedisplayed according to an embodiment of the present invention.

FIG. 151 is a view when an index is allocated according to the area andsize of an adjunct service object to be displayed

FIG. 152 is a view when an unavailable area of an object is designated.

MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be described belowin more detail with reference to the accompanying drawings. Theconfigurations and operations of the present invention shown in anddescribed with the accompanying drawings are explained as at least oneexample, and the technical idea of the present invention and its coreconfigurations and operations are not limited thereby.

The terms used in the present invention are selected as currently usedgeneral terms if possible in the consideration of functions of thepresent invention but could vary according to intentions or conventionsof those in the art or the advent of new technology. In certain cases,there are terms that are selected by an applicant arbitrarily, and insuch a case, their meanings will be described in more detail in thespecification. Accordingly, the terms used in the present inventionshould be defined on the basis of the meanings of the terms and contentsover the present invention not the simple names of the terms.

Moreover, among the terms in the present invention, a real time (RT)service literally means a service in real time. That is, the service istime-restricted. In contrast, a non-real time (NRT) service is a servicein NRT other than the RT service. That is, the NRT service is notrestricted by time. Furthermore, data for NRT service is called NRTservice data.

A broadcast receiver according to the present invention may receive NRTservice through a medium such as a terrestrial wave, a cable, and theinternet.

The NRT service may be stored in a storage medium of the broadcastreceiver, and then may be displayed on a display device according to apredetermined time or at the user's request. The NRT service is receivedin a file format, and is stored in a storage medium according anembodiment. The storage medium may be an HDD embedded in the broadcastreceiver according to an embodiment. As another example, the storagemedium may be a Universal Serial Bus (USB) memory or an external HDD,which is connected to the broadcast receiving system.

Signaling information is necessary to receive files constituting the NRTservice, store them in a storage medium, and provide a service to auser. The present invention may designate the above signalinginformation as NRT service signaling information or NRT servicesignaling data.

The NRT service includes Fixed NRT service and Mobile NRT serviceaccording to a method of obtaining IP datagram including NRT servicesignaling data. Especially, the Fixed NRT service is provided to a fixedbroadcast receiver, and the Mobile NRT service is provided to a mobilebroadcast receiver.

FIG. 1 is a conceptual diagram illustrating how RT service and NRTservice are provided.

A broadcasting station transmits the RT service according to atraditional way, that is, like current terrestrial broadcasting (ormobile broadcasting). At this point, the broadcasting station transmitsthe RT service, and then, by using a remaining bandwidth during thetransmission or an exclusive bandwidth, may provide the NRT service.That is, the RT service and NRT service are transmitted through the sameor different channel. Accordingly, in order for a broadcast receiver toseparate the RT service and the NRT service and store the separated NRTservice in order to provide it to a user if necessary, service signalinginformation (or NRT service signaling data) is required. The NRT servicesignaling information (or NRT service signaling data) will be describedin more detail later.

For example, a broadcasting station transmits broadcasting service datain real time and transmits news clip, weather information,advertisements, and Push VOD in non-real time. Additionally, the NRTservice may be specific scenes, detail information of a specificprogram, and preview in real-time broadcasting stream in addition tonews clip, weather information, advertisements, and Push VOD.

A typical broadcast receiver (i.e., a legacy device) may receive andprocess the RT service but may not receive and process the NRT service.That is, the typical broadcast receiver (i.e., a legacy device) is notinfluenced, in principle, by an NRT stream in a channel broadcasting RTservice. That is, even when receiving NRT service, the typical broadcastreceiver cannot process the received NRT service because it does notinclude a unit for processing it properly.

On the contrary, the broadcast receiver (i.e., an NRT device) of thepresent invention receives NRT service combined with RT service andproperly processes the NRT service, so that it provides more variousfunctions to a viewer than a typical broadcast receiver.

FIG. 2 is a view illustrating a structure of NRT service according to anembodiment.

The NRT service includes at least one content item (or content or NRTcontent) as shown in FIG. 2, and the content item includes at least onefile according to an embodiment. A file and object have the same meaningin the present invention.

The content item is a minimum unit playable independently. For example,news is provided in NRT. If the news includes business news, politicalnews, and lift news, it may be NRT service, and each may be designatedas a content item. Moreover, each of the business news, political news,and life news may include at least one file.

At this point, the NRT service may be transmitted in an MPEG-2 transportstream (TS) packet format through the same broadcasting channel as theRT service or an exclusive broadcasting channel. In this case, in orderto identify the NRT service, a unique PID may be allocated to the TSpacket of the NRT service data and then transmitted. According to anembodiment of the present invention, IP based NRT service data ispacketized into an MPEG-2 TS packet and then transmitted.

At this point, NRT service signaling data necessary for receiving theNRT service data is transmitted through an NRT service signalingchannel. The NRT service signaling channel is transmitted through aspecific IP stream on an IP layer, and at this point, this specific IPstream may be packetized into an MPEG-2 TS packet and then transmitted.The NRT service signaling data transmitted through the NRT servicesignaling channel may include at least one of a Service Map Table (SMT),an NRT Service Table (NST), an NRT Content Table (NCT), an NRTInformation Table (NRT-IT), and a Text Fragment Table (TFT). The NST orSMT provides access information on at least one NRT service operating onan IP layer, or the content items or files constituting the NRT service.The NRT-IT or NCT provides access information on the content items orfiles constituting the NRT service.

Additionally, NRT service signaling data including SMT (or NST) andNRT-IT (or NCT) may be included in a PSIP table on MPEG-2 TS or may betransmitted through an NRT service signaling channel on an IP layer in avirtual channel. Moreover, a plurality of NRT service data may beprovided through one virtual channel.

The NRT-IT includes information describing a content downloadable to bestored in a receiving device. Information provided to the NRT-IT mayinclude a content title (for example, the name of a downloadableprogram), available time for downloading content, contentrecommendation, availability of caption service, content identification,and other metadata.

Additionally, the TFT provides detailed description on a content item orservice. The TFT may include a data structure supporting multi languagesand, as a result, may represent detailed descriptions (e.g., each stringcorresponds to one language) in different languages. The text fragmenttable may be included in private sections having a table_id value (TBD)and may be identified by TFT_id. A TFT section may be included IPpackets in a service signaling channel, and a multicast IP address(224.0.23.60) and a port (4937) may be allocated to the servicesignaling channel by IANA.

First, a receiver may identify whether a corresponding service is theNRT service with reference to a service_category field in the SMT, forexample. Additionally, the receiver may uniquely identify the NRTservice from the SMT through an NRT_service_id field.

Additionally, the NRT service may include a plurality of content items.The receiver may identify an NRT content item through a content_id fieldin the NCT or NRT-IT. In addition, the NRT content item and NRT servicemay be connected to each other by matching the NRT_channel_id field ofthe NCT to the NRT_service_id field.

Moreover, the NRT service may be transmitted through a FLUTE session andthe receiver may extract FDT information from the FLUTE session. Then,content_id in the extracted FDT information is mapped into content_id ofNCT or OMA-BCAST SG in order to confirm and receive the NRT servicecontent that a user selects. If the mapping method is described briefly,for example, the receiver identifies each file constituting the NRTcontent item through the TOI and Content-Location fields in the FDT inthe FLUTE session. Each TOI or the Content-Location and content itemmaps the content_ID of the FDT into the content_id field of the NCT orthe content_id field of the OMA BCAST SG, so as to confirm and receivethe NRT service content.

FIG. 3 is a view illustrating a protocol stack for NRT service accordingto an embodiment.

For Fixed NRT service, the NRT service of a file format is IP-packetizedin an IP layer, and then, is transmitted in an MPEG-2 TS format througha specific channel.

Through an MPEG-2 based Program Specific Information (PSI) or Programand System Information Protocol (PSIP) table, for example, a VCT, it isdetermined whether there is NRT service in a virtual channel andidentification information of NRT service is signaled.

According to an embodiment, the NRT service signaling channel, whichtransmits NRT service signaling data signaling the access information ofthe IP based NRT service, is IP packetized into a specific IP stream inthe IP layer, and then, is transmitted in an MEPG-2 TS format.

That is, a broadcasting station packetizes the NRT content item or filesaccording to a file transfer protocol method as shown in FIG. 3, andthen, packetizes the packetized NRT content item or files in anAsynchronous Layered Coding (ALC) or Layered Coding Transport (LCT)method. Then, the packetized ALC or LCT data are packetized according toa UDP method. Then, the packetized UDP data is packetized according tothe IP method again, and then, becomes IP data. Here, the IP data mayinclude a File Description Table (FDT) having information on a FileDelivery over Unidirectional Transport (FLUTE) session. The packetizedIP data may be designated as IP datagram for convenience of descriptionin the present invention.

Additionally, the IP datagram of NRT service is encapsulated in anaddressable section structure and is packetized again in an MPET-2 TSformat. That is, one addressable section structure has a section headerand CRC checksum, which are added to one IP datagram. The format of theaddressable section structure is matched to a Digital Storage MediaCommand and Control (DSM-CC) section format for private datatransmission in terms of a structure. Accordingly, the addressablesection may be designated as a DSM-CC addressable section.

Moreover, NRT service signaling data including at least one of SMT (orNST) and NRT-IT (or NCT) necessary for receiving NRT content/files maybe transmitted through an NRT service signaling channel on an IP layer.Accordingly, the NRT service signaling data may be packetized accordingto an IP method in order to transmit it through the NRT servicesignaling channel on an IP layer. The NRT service signaling channel isencapsulated in the IP datagram having a well-known IP address and ismulti-casted according to an embodiment.

Additionally, the NRT service signaling data may be included in ProgramSpecific Information (PSI) or Program and System Information Protocol(PSIP) table section data and then transmitted. Moreover, the PSI tablemay include a Program Map Table (PMT) and a Program Association Table(PAT). The PSIP table may include a Virtual Channel Table (VCT), aTerrestrial Virtual Channel Table (TVCT), a Cable Virtual Channel Table(CVCT), a System Time Table (STT), a Rating Region Table (RRT), anExtended Text Table (ETT), a Direct Channel Change Table (DCCT), aDirect Channel Change Selection Code Table (DCCSCT), an EventInformation Table (EIT), and a Master Guide Table (MGT).

Furthermore, as data for digital rights management and encryption ofbroadcasting service to protect the NRT service from illegaldistribution and reproduction, BroadCast Services Enabler Suite DigitalRights Management (BCAST DRM) suggested by Open Mobile Alliance (OMA)may be used.

Moreover, the above mentioned Program Specific Information (PSI),Program and System Information Protocol (PSIP) table section data,DSM-CC addressable section data, and OMA BCAST DRM data are divided by a184 byte unit, and then, a 4 byte MPEG header is added to each 184 bytesin order to obtain a 188 byte MPEG-2 TS packet. At this point, a valueallocated to the PID of the MPEG header is a unique value identifying aTS packet for transmitting the NRT service and NRT service signalingchannel.

MPEG-2 TS packets may be modulated in a predetermined transmissionmethod in a physical layer, for example, an 8-VSB transmission method,and then, may be transmitted to a receiving system.

Moreover, FIG. 4 is a view illustrating a protocol stack for NRT serviceaccording to another embodiment.

FIG. 4 is view illustrating one example of the protocol stack for mobileNRT service. As shown in FIG. 4, an adaption layer is included betweenan IP layer and a physical layer. As a result, without using an MPEG-2TS format, the IP datagram of mobile service data and IP datagram ofsignaling information may be transmitted.

That is, a broadcasting station packetizes the NRT content/filesaccording to a file transfer protocol method as shown in FIG. 4, andthen, packetizes them according to an Asynchronous Layered Coding(ALC)/Layered Coding Transport (LCT) method. Then, the packetizedALC/LCT data are packetized according to a UDP method. Then, thepacketized ALC/LCT/UDP data is packetized again according to the IPmethod and becomes ALC/LCT/UDP/IP data. The packetized ALC/LCT/UDP/IPdata may be designated as IP datagram for convenience of description inthe present invention. At this point, OMA BCAST SG information undergoesthe same process as the NRT content/file to constitute IP datagram.

Additionally, when NRT service signaling information (for example, SMT)necessary for receiving the NRT content/files is transmitted through aservice signaling channel, the service signaling channel is packetizedaccording to a User Datagram protocol (UDP) method, and the packetizedUDP data is packetized again according to the IP method to become UDP/IPdata. The UDP/IP data may be designated as IP datagram for convenienceof description in the present invention. At the time, the servicesignaling channel is encapsulated in the IP datagram includingWell-known IP destination address and well-known destination UDP portnumber, and is multi-casted according to an embodiment.

In addition, in relation to OMA BCAST DRM for service protection, a UDPheader and an IP header are sequentially added to constitute one IPdatagram.

The IP datagram of the NRT service, NRT service signaling channel, andmobile service data are collected in an adaption layer to generate a RSframe. The RS frame may include IP datagram of OMA BCAST SG.

The length (i.e., the number of rows) of a column in the RS frame is setby 187 bytes, and the length (i.e., the number of columns) of a row is Nbytes (N may vary according to signaling information such as atransmission parameter (or TPC data).

The RS frame is modulated in a predetermined transmission method in amobile physical layer (for example, VSB transmission method) and then istransmitted to a receiving system.

Moreover, whether the NRT service is transmitted is signaled through aPSI/PSIP table. As one example, whether the NRT service is transmittedis signaled to the VCT or TVCT.

FIG. 5 is a view illustrating a bit stream section of a TVCT tablesection (VCT) according to an embodiment.

Referring to FIG. 5, the TVCT table section has a table form of anMPEG-2 private section as one example, but is not limited thereto.

When the VCT and PID of the audio/video are parsed and then transmittedthrough the TVCT, the packet identification (PID) information may beobtained.

Accordingly, the TVCT table section includes a header, a body, and atrailer. A header part ranges from a table_id field to aprotocol_version field. A transport_stream_id field is a 16 bit fieldand represents an MPEG-2 TS ID in a program association table (PAT)defined by a PID value of 0 for multiplexing. In a body part, anum_channels_in_section field is an 8 bit field and represents thenumber of virtual channels in a VCT section. Lastly, a trailer partincludes a CRC_(—)32 field.

A service_type field (6 bits) represents a type of service transmittedfrom a virtual channel. FIGS. 6 and 7 are views illustrating how todefine a value of a service_type field according to an embodiment.According to an embodiment, a service_type value (i.e., ‘0x04’) shown inFIG. 6 means that service_type is ATSC_data_only_service and NRT serviceis transmitted through a virtual channel. According to anotherembodiment, a service_type value (i.e., ‘0x08’) shown in FIG. 7 meansthat service_type is ATSC_nrt_service and a virtual channel provides NRTservice satisfying the ATSC standard.

FIG. 8 is view of data_service_table_section) for identifying anapplication of NRT service and bit stream syntax ofdata_service_table_bytes in a DST section. A broadcasting station NRTservice data or NRT service signaling data, satisfying ASTC standard,may be transmitted through the DST table section of FIG. 8.

Hereinafter, semantic of fields including a data_service_table_sectionstructure is as follows.

A table_id field (8 bits) as a field for type identification of acorresponding table section is a table section in which a correspondingtable section constitutes DST through this field. For example, areceiver identifies that a corresponding table section is a tablesection constituting DST if a value of the field is 0XCF.

A section_syntax_indicator field (1 bit) is an indicator defining asection format of DST, and the section format may be short-form syntax(0) of MPEG, for example.

A private_indicator field (1 bit) represents whether the format of acorresponding section follows a private section format and may be setwith 1.

A private_section_length field (12 bits) represents a remaining tablesection length after a corresponding field. Additionally, a value ofthis field does not exceed ‘0xFFD’.

A table_id_extension field (16 bits) is dependent on a table, and may bea logical part of a table_id field providing a range of the remainingfields.

A version_number field (5 bits) represents the version number of DST.

A current_next_indicator field (1 bit) indicates whether a transmittedDST table section is applicable currently. If the field value is 0, itmeans that there is no table yet and the next table is valid.

A section_number field (8 bits) represents a section number in sectionsin which a corresponding table section constitutes a DST table.section_number of the first section in DST is set with ‘0x00’. Thesection_number is increased by one as the section of DST is increased.

A last_section_number field (8 bits) represents the last section numberconstituting a DST table, i.e., the highest section_number.

data_service_table_bytes represents a data block constituting DST, andits detailed structure will be described below.

A CRC_(—)32 field is a 32 bit field and includes a cyclic redundancycheck (CRC) value, which ensures zero output from registers of a decoderdefined in an MPEG-2 system after processing an entire DST section.

Hereinafter, semantic of fields including a data_service_table_bytesstructure is as follows.

An sdf_protocol_version field (8 bits) describes the version of aService Description Framework protocol.

An application_count_in_section field (8 bits) represents the number ofapplications listed in a DST section.

A compatibility_descriptor( ) field represents that a correspondingstructure includes a DSM-CC compatible descriptor. Its purpose is tosignal compatible requirements of an application in a receiving platformin order to use a corresponding data service after determining itsability.

An app_id_byte_length field (16 bits) describes the number of bytes usedfor identifying an application.

An app_id_description field (16 bits) describes the format and semanticof the following application identification bytes. For example, a valueof an app_id_description may be defined as Table 1.

TABLE 1 Value Application Identifier Format 0x0000 DASE application0x0001-0x7FFF ATSC reserved 0x8000-0xFFFF User private

An app_id_byte field (8 bits) represents a byte of an applicationidentifier.

A tap_count field (8 bits) describes the number of Tap( ) structuresused for corresponding application.

A protocol_encapsulation field (8 bits) describes a protocolencapsulation type used for transmitting a specific data elementreferenced by a Tap( ) field. A value of the protocol_encapsulationfield is defined as Table 2.

TABLE 2 Value Encapsulated Protocol 0x00 Not in a MPEG-2 TransportStream 0x01 Asynchronous non-flow controlled scenario of the DSM-CCDownload protocol encapsulated in DSM-CC sections 0x02 Non-streamingSynchronized Download protocol encapsulated in DSM-CC sections 0x03Asynchronous multiprotocol datagrams in Addressable Sections usingLLC/SNAP header 0x04 Asynchronous IP datagrams in Addressable Sections0x05 Synchronized streaming data encapsulated in PES 0x06 Synchronousstreaming data encapsulated in PES 0x07 Synchronized streamingmultiprotocol datagrams in PES using LLC/SNAP header 0x08 Synchronousstreaming multiprotocol datagrams in PES using LLC/SNAP header 0x09Synchronized streaming IP datagrams in PES 0x0A Synchronous streaming IPdatagrams in PES 0x0B Proprietary Data Piping 0x0C SCTE DVS 051asynchronous protocol [19] 0x0D Asynchronous carousel scenario of theDSM-CC Download protocol encapsulated in DSM-CC sections 0x0E Reservedfor harmonization with another standard body 0x0F-0x7F ATSC reserved0x80-0xFF User defined

An action_type field (7 bits) represents attribute of data referenced bya Tap( ).

A resource_location field (1 bit) describes a position of anassociation_tag field matching to an association_tag value listed in thenext Tap structure. When a corresponding field is set with 0,association_tag exists in PMT of a current MPEG-2 program. Like this,when the corresponding field is set with 1, a matching association_tagexits in DSM-CC Resource Descriptor in a Network Resources Table of acorresponding data service.

A Tap( ) field may include information on searching a data element of anapplication state in a communication channel of a lower layer. Anassociation_tag field in a Tap( ) field may include correspondenceinformation between data elements of an application state. A value of anassociation_tag field in one Tap structure corresponds to a value of anassociation_tag field of one association tag descriptor in a currentPMT. For example, a Tap( ) field may have a specific structure includingfields of Table 3.

TABLE 3 Syntax No. of bits Format Tap ( ) { tap_id 16 uimsbf use 16uimsbf association_tag 16 uimsbf selector( ) }

A tap_id field (16 bits) is used by an application to identify dataelements. A value of tap_id has a range defined by values of app_id_bytefields related to Tap( ) in DST. A tap_id value is selected by a dataservice provider. Additionally, the tap_id value may be used forapplication to deal with a data element.

A Use field (16 bits) is used to specify a communication channelreferenced by association_tag.

An association_tag field (16 bits) uniquely identifies one of a DSM-CCresource descriptor listed in a Network Resource Table or dataelementary stream listed in PMT. A value of a corresponding field may beidentical to an association_tag value of association_tag_descriptor.

A Selector( ) field describes a specific data element available in acommunication channel or data elementary stream referenced by theassociation_tag field. Additionally, the selector structure may indicatea protocol required for a corresponding data element.

A tap_info_length field (16 bits) describes the number of bytes ofdescriptors in the next of a corresponding field.

A descriptor( ) field may include descriptor information according to acorresponding descriptor format.

An app_info_length field (8 bits) describes the number of bytes of thenext descriptors of a corresponding field.

A descriptor( ) field may include descriptor information according to acorresponding descriptor format.

An app_data_length field (16 bits) describes the length of a byte unitof app_data_byte fields.

An app_data_byte (8 bits) field represents input parameters related toapplication and other private data fields in 1 byte.

A service_info_length field (8 bits) describes the number of byte unitsof the next descriptor.

A descriptor( ) field may include descriptor information according to acorresponding descriptor format.

A service_private_data_length field (16 bits) describes the length of abyte unit in private fields.

A service_private_data_byte field (8 bits) represents a private field in1 byte.

FIG. 9 is a view illustrating a method of receiving and providing NRTservice in a receiving system by using ATSC A/90 standard fortransmitting data broadcasting stream and ATSC A/92 standard fortransmitting IP multicast stream.

That is, information on stream constituting each virtual channel issignaled to service location descriptor of VCT or ES_loop of PMT. Forexample, as shown in FIG. 7 or 8, if VCT service type is 0x02(i.e.,digital A/V/Data), 0x04(i.e., Data only), or 0x08(i.e., NRT Onlyservice), NRT service stream may be transmitted to the virtual channel.At this point, if 0x95(i.e., DST transmission) is allocated to astream_type field value in a service location descriptor (or ES loop ofPMT), it means that broadcast is transmitted. If the stream_type fieldvalue has no value or is not 0x95, only typical A/V is transmitted. Thatis, if the stream_type field value in service location descriptor has0x95, an Elementary_PID field value at this point is a PID value of aData Service Table (DST). Accordingly, DST may be received through theElementary_PID.

Through the DST, types of application and detailed information on databroadcasting stream transmitted through the channel may be obtained. TheDST is used to identify NRT application (i.e., NRT service).

That is, the App_id_descrption field of DST defines the format andinterpretation of the following application identification bytes.According to an embodiment, ‘0x0003’ is allocated to theApp_id_descrption field to identify NRT application. The above numericalvalue is just one example, and does not restrict the range of the rightsof the present invention.

If the App_id_descrption field value is ‘0x0003’, the next followingApplication_id_byte value becomes a Service ID value of the NRTapplication. A service ID for the NRT application may have a URI valueuniquely identifying a corresponding service around the world.

After the NRT application is identified, PID of an MPEG-2 TS packetdivided from the IP datagram of an NRT service signaling channel issearched through Tap information. Then, IP datagram transmitting a NRTservice signaling channel may be obtained from MPEG-2 TS packets havingPID obtained through the tap information, and NRT service signaling datamay be obtained from the obtained IP datagram. At this point, the IPaccess information of the NRT service signaling channel may bewell-known IP access information, i.e., well-known IP address andwell-known UDP port number.

That is, if the Protocol_encapsulation field value in the DST is 0x04,asynchronous IP stream is transmitted, and if the Selector_type fieldvalue is 0x0102, a device_id value indicating destination address may bedelivered through selector_bytes.multiprotocol_encaplsulation_descriptor is used to accurately interpretthe selector_bytes value and the number of valid bytes in the device_idvalue is signaled. As a result, through the Tap information, an IPMulticast address (or address range) of the NRT service signalingchannel, transmitted to the corresponding PID, is obtained.

Accordingly, a receiver accesses the Multicast address (or addressrange) to receive IP stream, i.e., IP packet, and then, extracts NRTservice signaling data from the received IP packet.

Then, the receiver receives NRT service data, i.e., NRT contentitem/files to store them in a storage medium or display them on adisplay device, on the basis of the extracted NRT service signalingdata.

According to another embodiment, a Stream Type field value of DST mayhave new 0x96 instead of 0x95 to signal NRT service. This is because NRTservice, i.e., new application, may malfunction when a typical receiverdetermines whether there is data broadcasting stream only on the basisof whether there is stream having a stream type of 0x95. In this case,with designating a stream newly, a typical receiver may disregard it toguarantee backwards compatibility.

FIGS. 10 and 11 are views illustrating a method of receiving NRT serviceby using DSM-CC addressable section data according to anotherembodiment.

A data transmission method using DST is a standard for transmitting allkinds of IP datagram through digital broadcasting stream, and may beinefficient for the NRT service. Accordingly, FIGS. 10 and 11 illustratea method of receiving the NRT service by signaling the PID of a specificstream including IP address information and section data of the IPdatagram with respect to the NRT service through the data of the DSM-CCaddressable section.

As shown in FIG. 10, the receiver may obtain information that NRTservice stream is transmitted through the virtual channel when a servicetype of VCT (or TVCT) is 0x08 (i.e., NRT Only service). That is, thereceiver may obtain information on whether there is NRT serviceaccording to service_type information by mapping the PID of a virtualchannel into a channel number.

At this point, if 0x0D is allocated to a stream_type field value inservice location descriptor of VCT (or ES loop of PMT), it means thatDSM-CC stream is transmitted. An Elementary_PID field value at thispoint may be the PID value of a DSM-CC addressable section. Accordingly,the receiver receives a DSM-CC addressable section including NRT servicedata through Elementary_PID.

That is, the receiver may obtain the PID of the DSM-CC addressablesection through VCT or PMT. Here, the receiver may obtain anNRT_IP_address_list_descriptor_A( ) field including an IP address of anNRT service signaling channel or an IP address of the FLUTE session fortransmitting NRT service data, which corresponds to the PID obtainedfrom PMT of the corresponding stream.

Moreover, the receiver may receive DSM-CC addressable section data fromIP multicast stream or IP subnet on the basis of the IP address obtainedfrom an NRT_IP_address_list_descriptor_A( ) field. The receiver mayobtain a corresponding IP datagram including a specific NRT service (forexample, A, B, or C) data by searching a DSM-CC addressable sectionhaving PID corresponding to the obtained elementary_PID from thereceived DSM-CC addressable section data.

FIG. 11 is a view illustrating a method of signaling a DSM-CCaddressable section data by using VCT according to another embodiment.

As mentioned above, the receiver may obtain information that NRT servicestream may be transmitted when a service_type in VCT is 0X02, 0X04 of0X08. Also, the receiver may obtain elementary_PID having a stream typeof 0X0D from the service_location_descriptor( ) field to receive theDSM-CC stream. Here, the receiver may obtain anNRT_IP_address_list_descriptor_B( ) field including an IP address of anNRT service signaling channel or an IP address of the FLUTE session fortransmitting NRT service data, which corresponds to the obtainedelementary_PID.

Moreover, the receiver may receive DSM-CC addressable section data fromIP multicast stream or IP subnet on the basis of the IP address obtainedfrom an NRT_IP_address_list_descriptor_B( ) field. The receiver mayobtain the IP datagram including specific NRT service (for example, A,B, or C) that it wants to receive from the received DSM-CC addressablesection data by parsing the DSM-CC addressable section having PIDcorresponding to the obtained elementary_PID.

The processes for extracting NRT service signaling data and NRT servicedata are described as follows. Here, 0x08 is allocated to theservice_type field value in VCT, and indicates that at least one NRTservice is transmitted to a corresponding virtual channel.

That is, when the receiver is turned on and a channel is selected bydefault or a user through a tuner, the PSI/PSIP section handler obtainsVCT and PMT from a broadcast signal received through the selectedchannel. Also, the PSI/PSIP section handler parses the obtained VCT toconfirm whether there is NRT service. This is confirmed by checking theservice_type field value in a virtual loop of the VCT. For example, whenthe service_type field value is not 0x08, the corresponding virtualchannel does not transmit NRT service. At this point, since the virtualchannel transmits existing service (i.e., legacy ATSC service), thereceiver operates properly according to information in the virtualchannel.

Additionally, in relation to a demultiplexing unit, if a service_typefield value is 0x08 according to a control of a service manager, acorresponding virtual channel transmits NRT service. In this case, PIDof DST is extracted by parsing a service location descriptor in avirtual channel loop of the VCT. Moreover, DST is received by using theextracted PID.

Moreover, the receiver confirms whether a corresponding service providedthrough a channel selected from the received DST is NRT service.

The NRT service is confirmed by an App_id_descrption field value.

According to an embodiment, ‘0x0003’ is allocated to theApp_id_descrption field to identify NRT application. The above numericalvalue is just one example, and does not restrict the range of the rightsof the present invention.

If the App_id_descrption field value in the DST is ‘0x0003’, the nextfollowing Application_id_byte value becomes a Service ID value of theNRT application (i.e., NRT service). Therefore, the service manager orPSI/PSIP section handler extracts Tap( ) to PID of an MEGP-2 TS packetseparated from the IP datagram of the NRT service signaling channelafter identifying the NRT application (i.e., NRT service). Then, streamPID including association_tag of the extracted Tap is extracted fromPMT.

Also, the addressable section handler may recover the DSM-CC addressablesection by removing decapsulation, i.e., an MPEG-2 header, afterreceiving MPEG-2 TS packets corresponding to the extracted stream PID.

Then, the receiver recovers the IP datagram transmitting an NRT servicesignaling channel by removing a section header and CRC checksum from theDSM-CC addressable section and obtains NRT service signaling data fromthe recovered IP datagram. Here, access information on the IP datagramtransmitting the NRT service signaling channel is a well-knowndestination IP address and a well-known destination UDP port number.

That is, if the Protocol_encapsulation field value in the DST is 0x04,asynchronous IP stream is transmitted, and if the Selector_type fieldvalue is 0x0102, a device_id value indicating a destination address maybe delivered through selector_bytes.multiprotocol_encaplsulation_descriptor is used to accurately interpretthe selector_bytes value and the number of valid bytes in the device_idvalue is signaled. As a result, through the Tap information, an IPMulticast address (or address range) of the NRT service signalingchannel, transmitted to the corresponding PID, is obtained.

Accordingly, a receiver accesses the Multicast address (or addressrange) to receive IP stream, i.e., IP packet, and then, extracts NRTservice signaling data from the received IP packet.

The receiver receives NRT service data, i.e., NRT content item/files tostore them in a storage medium or display them on a display device, onthe basis of the extracted NRT service signaling data.

Moreover, the NRT service may be provided Dynamic Content Delivery (DCD)service according to an embodiment. The DCD service is service fortransmitting content to a receiver periodically or at the user request,and the content is selected from a server according to receiverinformation. The DCD service supports a point-to-point method and abroadcast method in a communication means for content delivery, and theabove NRT service is transmitted through an OMA BCAST method and one ofthe broadcast methods of the DCD service.

NRT service data may be transmitted through the DCD service of the OMABCAST method. In this case, the receiver may obtain the DCD channelinformation to receive NRT service and may receive the NRT servicethrough a corresponding DCD channel on the basis of the DCD channelinformation.

Moreover, the DCD channel information may be included in the NST andtransmitted. For example, the receiver receives NST, and obtains DCDchannel information through DCD bootstrap.

Additionally, the NST may include DCD channel metadata, received througha DCD administrative channel, for signaling of the DCD channelinformation. Accordingly, the receiver may obtain information on achannel for receiving NRT service and metadata through NST.

Accordingly, when NST including DCD channel information is transmitted,the receiver accesses the DCD channel through NST without transmissionof the NRT service signal data, and then receives the NRT service.

Like this, if NST includes metadata of a channel for receiving NRTservice, there are several advantages.

First, without receiving the NRT service signaling data on the basis ofthe service type of a virtual channel, service access speed may beincreased by receiving channel metadata that directly receives NRTservice from NST.

Additionally, update signaling for a channel change item may beperformed in real time in a broadcast environment.

Moreover, access information in OMA BCAST SG may be obtained byreferring to NST. For example, the receiver receives DCD channel metadata on the basis of the DCD channel information in NST, and obtainsaccess information to receive NRT service on the basis of the NRTservice signaling data and DCD channel metadata obtained from NST.

Lastly, NST including a list of NRT service related to another virtualchannel may be transmitted. Accordingly, list information of the NRTservice may be transmitted through a specific NRT service signalingchannel on an IP layer not on a PSI or PSIP layer. Accordingly, in thiscase, backwards compatibility to PSI or PSIP may be reserved.

In addition, as mentioned above, the DCD channel information includingthe DCD channel metadata may be included in the access information of SGin OMA BCAST, and the access information corresponds to the NRT serviceinformation in NST. In more detail, the receiver may obtain NRT serviceinformation in NST from an access fragment of OMA BCAST SG. Accordingly,the receiver may obtain information on receiving NRT service byreceiving NST corresponding to the obtained NRT service information.

Moreover, the NRT service transmitted through the DCD channel may bedivided by a service category allocated. For example, the servicecategory of the NRT service transmitted through the DCD channel may beidentified by 0X0F.

FIGS. 12 and 13 are views illustrating a bit stream syntax of NSTaccording to an embodiment.

Here, the corresponding syntax is created in an MPEG-2 private sectionformat to help understanding, but the format of the corresponding datamay vary. For example, the corresponding data may be expressed in aSession Description Protocol (SDP) format and signaled through a SessionAnnouncement Protocol (SAP) according to another method.

NST describes service information and IP access information in a virtualchannel for transmitting NST, and provides NRT broadcast streaminformation of a corresponding service by using an identifier of the NRTbroadcast stream, i.e., NRT_service_id, in each service. Furthermore,the NST describes description information of each fixed NRT service inone virtual channel, and a descriptor area may include other additionalinformation.

A num_NRT_services field (8 bits) represents the number of NRT servicesin an NST section.

Additionally, NST provides information on a plurality of fixed NRTservices by using a ‘for’ loop. Hereinafter, the same field informationmay be provided to each fixed NRT service.

An NRT_service_id field (16 bits) is an indicator that uniquelyidentifies a corresponding NRT service in a range of a corresponding NRTbroadcast. The NRT_service_id is not changed during the correspondingservice. Here, if the service is terminated, in order to evadeconfusion, NRT_service_id for the service may not be used for anotherservice until an appropriate time elapses.

Additionally, NST provides information on a plurality of components byusing a ‘for’ loop. An essential_component_indicator field (1 bit)indicates when a value of a corresponding value is set with 1 that acorresponding component is a necessary component for NRT service. Ifnot, the corresponding component is a selected component.

A port_num_count field (6 bits) indicates numbers of UDP ports relatedto a corresponding UDP/IP stream component. Values of the destinationUDP port numbers are increased by one, starting from acomponent_destination_UDP_port_num field value.

A component_destination_IP_address_flag field (1 bit) is a flagrepresenting that there is a component_destination_IP_address field forcorresponding component if set with 1.

In relation to component_destination_IP_address field (128 bits), ifcomponent_destination_IP_address_flag is set with 1, there iscorresponding field, but if component_destination_IP_address_flag is setwith 0, there is no corresponding field. If there is a correspondingfield, the corresponding field includes a source IP address of all IPdatagram transmitting components of the corresponding NRT service. Arestricted use of a 128 bit long address of a corresponding field is forfuture use of IPv6, which is not currently used though.

A component_destination_UDP_port_num field (16 bits) represents adestination UDP port number for corresponding UDP/IP stream component.

A num_component_level_descriptors field (4 bits) provides the number ofdescriptors providing additional information on corresponding IP streamcomponent.

A component_level_descriptors field identifies at least one descriptorproviding additional information on a corresponding IP stream component.

A num_NRT_service_level_descriptors field (4 bits) represents the numberof NRT service level descriptors for corresponding service.

NRT_service_level_descriptor( ) identifies no or at least one descriptorproviding additional information on corresponding NRT service. Here, aspecific service type for NRT service may be provided. The specificservice type includes a portal service providing web content, push VOD,and A/V download.

A num_virtual_channel_level_descriptors field (4 bits) describes thenumber of virtual channel level descriptors for a corresponding virtualchannel.

virtual_channel_level_descriptor( ) represents a descriptor providingadditional information on a virtual channel that a corresponding NSTdescribes.

Moreover, NRT service is transmitted through FLUTE, and accessinformation on the NST table is connected to FLUTE session informationas follows.

Source_IP_address is a source IP address of the same server transmittingall channels of the FLUTE session.

NRT_service_destination_IP_Address is signaled if there is a destinationIP address of a session level of the FLUTE session.

A component may be mapped into a channel in the FLUTE session, and anadditional destination IP address (which is different from an IP addresssignaled by session) is signaled throughcomponent_destination_IP_address at each channel.

Additionally, a destination port number is signaled throughcomponent_destination_UDP_port_num and the number of destination portsstarting from component_destination_UDP_port_num may be additionallydesignated through port_num_count.

A plurality of channels may be configured for one destination IP addressby designating a port in plurality. Here, one component designates aplurality of channels. However, it is desired to identify a channelthrough a destination IP address in general. Here, one channel istypically mapped into one component.

Content items/files for NRT service are transmitted through FLUTE, andcorresponding FLUTE session information is signaled using accessinformation on the NST table.

FIG. 14 is a view illustrating a bit stream syntax ofNRT_component_descriptor (MH_component_descriptor) according to anembodiment.

NRT_component_descriptor( ) is shown in a component descriptor loop ineach component of each NRT service in NST. Then, all parameters in acorresponding descriptor correspond to parameters used for components ofNRT service.

Hereinafter, each field information transmitted through theNRT_component_descriptor of FIG. 14 will be described as follows.

A component_type field (7 bits) identifies an encoding format of acomponent. The identification value may be one of values allocated forpayload_type of a RTP/AVP stream. Additionally, the identification valuemay be a dynamic value ranging from 96 to 127. Values of the field forcomponents constituting media transmitted through RTP are identical tothose in payload_type in an RTP header of IP stream transmitting acorresponding component.

An adding value of a component_type field in a range of 43 to 71 will bedefined in the future version of the standard. When NRT service streamis transmitted based on FLUTE, in order to additionally signalparameters (described below) necessary for FLUTE session, 38 (which iscomponent_type defined for a FLUTE component in ATSC) may be used, or 43(i.e., an unallocated value) may be defined as component_type for newNRT transmission, and used.

A num_STKM_streams field (8 bits) identifies numbers of STKM streamsrelated to a corresponding component.

A STKM_stream_id field (8 bits) identifies STKM stream having keys inorder to decrypt the obtained corresponding protected component. Here,the STKM_stream_id field in the component descriptor for the STKM streamis referred.

An NRT_component_data (component_type) field provides at least one ofencoding parameters necessary for expressing a corresponding componentand other parameters. Here, a structure of an NRT_component_data elementis determined by a value of a component_type field.

A File Delivery Table (FDT) of FLUTE sessions is used for deliveringitem lists of all content items, and provides sizes, data types, andother information of items related to obtain the items.

Accordingly, the present invention obtains information for accessing theFLUTE session transmitting a corresponding content by using NST, inorder to receive a selected content from SG obtained by using NRT-IT.Moreover, the present invention maps information in a file transmittedthrough a corresponding FLUTE session into information on a content itemof NRT-IT. In this case, identification of service including theselected content item is resolved through NRT_service_id of the NST.

NRT service is transmitted through FLUTE, and access information on theNST table is connected to FLUTE session information as follows.

A component may be mapped into a channel in the FLUTE session, and anadditional destination IP address (which is different from an IP addresssignaled by session) is signaled throughcomponent_destination_IP_address at each channel. Additionally, adestination port number is signaled throughcomponent_destination_UDP_port_num and the number of destination portsstarting from component_destination_UDP_port_num may be additionallydesignated through port_num_count.

A plurality of channels may be provided to one destination IP address bydesignating a plurality of ports, and in such a case, one componentdesignates a plurality of channels. However, it is recommended that achannel be distinguished through a destination IP address, and in such acase, one channel is mapped into one component.

component_attribute_byte may be used to signal an additional attributeof a component constituting a session. Additional parameters necessaryfor signaling a FLUTE session may be signaled through this.

In this regard, parameters for signaling the FLUTE session are required,and include definitely necessary required parameters and optionalnecessary parameters related to a corresponding FLUTE session.

FIG. 15 is a view illustrating a bit stream syntax of NRT componentdescriptor including NRT_component_data according to an embodiment.

One NRT service may be included in multiple FLUTE sessions. Each sessionmay be signaled using at least one NRT component descriptors dependingon IP addresses and ports used for the session.

This FLUTE component descriptor may be delivered through aComponent_level_descriptor loop of NST. If the FLUTE channel is inplurality, since TSI and session_start_time, session_end_Time, i.e.,parameters of a session level, should be signaled once, a FLUTEcomponent descriptor may be transmitted only in one of components inseveral channels through a Component_level_descriptor loop.

FIG. 16 is a view illustrating a bit stream syntax of NRT-IT section forsignaling NRT application according to an embodiment.

Information provided from NRT-IT includes a title of content (forexample, a name of downloadable program), download available time andinformation, content advisories, caption service availability, contentidentification, and other metadata. One item of content may include atleast one file. For example, an audio/video clip may be played in a JPEGthumbnail image used for displaying a screen.

An instance of NRT-IT may include data corresponding to an arbitrarilypredetermined period, or may describe a NRT content starting at apredetermined time and ends at the indefinite future. Each NRT-ITrepresents a start time and a duration period that may be indefinite.Each NRT-IT instance may be divided into 256 sections. Each sectionincludes information on a plurality of content items. Information of aspecific content item cannot be divided and stored in at least twosections.

The downloadable content item, which is more extended than a period thatat least one NRT-IT instance takes, is the first of NRT-IT. The contentitem description is stored in NRT_information_table_section ( ) in anavailability order. Accordingly, when a value of last_section_number isgreater than 0 (it means that NRT-IT is transmitted to a plurality ofsections), all content item description in a specific section not thefirst section may have the same as or higher availability than thecontent item description of the next section.

Each NRT-IT identifies an NRT service related to a specific value of avalid service_id in a specific virtual channel during the period.

A num_items_in_section field (8 bits) represents the number of contentitems described in an NRT-IT section.

A content_linkage field (16 bits) represents an identification numberwithin a range from 0x0001 to 0xFFFF. 0x0000 is not used.content_linkage is a linkage function for two: this links at least onefile of FLUTE FDT related to NRT service with metadata of NRT-IT andforms TF_id (identifier for Text Fragement in Text FragmentTable). Avalue of a content_linkage field corresponds to a value of anFDTCotent-Linkage element or a value of a File-Content-Linkage elementin FLUTE FDT of each file related to a content item. A priority rule isapplied when each content linkage value including a correspondingcontent linkage element in FLUTE FDT is matched.

content_descriptor is a descriptor that is additionally applied to eachcontent item.

FIG. 17 is a view illustrating a syntax structure of bit stream for NRTsection (NRT_content_table_section) according to an embodiment. Detaileddescription of each field in the NCT section is as follows.

In FIG. 17, a table_id field (8 bits) as the identifier of a tableincludes an identifier identifying NCT.

A content_id field (16 bits) indicates an identifier uniquelyidentifying the content (or file).

That is, the receiver uses the NCT to obtain configuration informationon NRT content/file, and provides a guide for the NRT/file on the basisof the obtained configuration information on NRT content/file. Moreover,the receiver obtains access information of FLUTE session, whichtransmits the content/file selected by the guide, from NST, and receivesthe selected content by using the obtained FLUTE session accessinformation.

Moreover, the present invention may include container information,encoding information, and decoding parameters of media objects,necessary for rendering of the content/files constituting NRT service,in the NCT, and then transmit it. Accordingly, a receiving systemextracts the container information, the encoding information, and thedecoding parameters of media objects by each content, necessary forrendering of the corresponding content/files, and uses them inrendering.

FIG. 18 is a view illustrating a bit stream syntax structure of an SMTsession providing signaling information on NRT service data according toan embodiment.

Here, the corresponding syntax is created in an MPEG-2 private sectionformat to help understanding, but the format of the corresponding datamay vary.

The SMT describes signaling information (or signaling information of NRTservice) and IP access information of a mobile service in Ensemble inwhich SMT is transmitted. The SMT uses Transport_Stream_ID, i.e., anidentifier of broadcast stream including each service, and providesbroadcasting stream information of a corresponding service. Furthermore,SMT includes description information of each mobile service (or NRTservice) in one Ensemble, and includes other additional information in adescriptor area.

As mentioned above, the SMT session may be included as the IP streamformat in the RS frame, and then, transmitted. In this case, RS framedecoders of a receiver describe later decode inputted RS frames, andoutputs the decoded RS frames as a corresponding RS frame handler.Moreover, each RS frame handler divides the inputted RS frame by a rowunit to constitute M/H TP, and outputs it as an M/H TP handler.

In addition, examples of fields transmitted through SMT are as follows.

A table_id field (8 bits) is a field indicating a table type, andthrough this, it is confirmed that this table section is a table sectionin SMT.

A num_services field (8 bits) indicates the number of services in an SMTsession. At least one mobile service, at least one NRT service, ormobile and NRT services may be received through Ensemble having the SMT.If only NRT services are transmitted through the Ensemble having SMT, itmay indicate the number of NRT services in the SMT.

Later, a ‘for’ loop (or a service loop) is performed as many times asthe number of services corresponding to the num_service field value, toprovide signaling information on a plurality of services. That is,signaling information of a corresponding service is displayed by eachservice in the SMT session. Here, the service may be mobile or NRTservice. At this point, the following field information may be providedto each service.

A service_id field (16 bits) represents a value uniquely identifying acorresponding service (A 16-bit unsigned integer number that shalluniquely identify this service within the scope of this SMT section.).The service_id of a service shall not change throughout the life of theservice.

If a service is terminated, then the service_id for the service shouldnot be used for another service until after a suitable interval of timehas elapsed. Here, if the service is NRT service, the service_id mayidentify the NRT service.

A short_service_name_length field (3 bits) represents the length of ashort service name in a short_service_name field in byte unit.

A short_service_name field represents a short name of a correspondingservice. For example, if the service is mobile service, a short name ofthe mobile service is displayed, and if it is NRT service, a short nameof the NRT service is displayed.

A service_category field (6 bits) identifies a type category of acorresponding service. If a value of a corresponding field is set with avalue indicating “informative only”, it is dealt as an informativedescription for the category of the service. And, a receiver is requiredto test a component_level_descriptors( ) field of SMT in order toidentify an actual category of the received service. Theservice_category field has an NTP time based component for serviceshaving video and/or audio component.

Especially, in regards to the present invention, if a service_categoryfield value has ‘0x0E’, a corresponding service indicates NRT service.In this case, it is indicated that signaling information of servicecurrently described in an SMT session is signaling information of NRTservice.

If the service is NRT service, the Source_IP_address field becomes asource IP address of the same server transmitting all channels of theFLUTE session.

Additionally, SMT provides information on a plurality of components byusing a ‘for’ loop.

Later, a ‘for’ loop (or a component loop) is performed as many times asthe number of components corresponding to the num_components fieldvalue, to provide access information on a plurality of components. Thatis, access information on each component in a corresponding service isprovided. At this point, the following field information on eachcomponent may be provided. Here, one component corresponds to one FLUTEsession according to an embodiment.

A num_component_level_descriptors field (4 bits) indicates the number ofdescriptors providing additional information on a component level.

component_level_descriptor( ) fields are included in the component loopas many as a number corresponding to the num_component_level_descriptorsfield value, so that additional information on the component isprovided.

A num_service_level_descriptors field (4 bits) indicates the number ofdescriptors providing additional information on a corresponding servicelevel.

service_level_descriptor( ) fields are included in the service loop asmany as a number corresponding to the num_service_level_descriptorsfield value, so that additional information on the service is provided.If the service is mobile service, additional information on the mobileservice is provided, and if it is NRT service, additional information onthe NRT service is provided.

A num_ensemble_level_descriptors field (4 bits) indicates the number ofdescriptors providing additional information on an ensemble level.

ensemble_level_descriptor( ) fields are included in the ensemble loop asmany as a number corresponding to the num_ensemble_level_descriptorsfield value, so that additional information on the ensemble is provided.

Moreover, component_descriptor( ) as component_level_descriptors( ) maybe provided to SMT of FIG. 18.

The component_descriptor( ) is used as one ofcomponent_level_descriptors( ) of SMT, and describes additionalsignaling information of a corresponding component.

Accordingly, in relation to mobile NRT service, signaling informationnecessary for receiving a corresponding FLUTE session may be providedusing the component descriptor of FIG. 14.

For example, if a component_type field value of the component descriptorof FIG. 14 is 38, a component_data (component_type) field provides datafor FLUTE file delivery as shown in FIG. 15. Since each fielddescription of FIGS. 14 and 15 is made above, overlapping descriptionswill be omitted.

FIG. 19 is a view illustrating an FDT schema for mapping a file andcontent_id according to an embodiment. FIG. 20 is a view illustrating anFDT schema for mapping a file and content_id according to anotherembodiment. They represent an FDT instant level entry file designatingmethod. NRT content includes a plurality of files. However, since eachfile has no mark, it is difficult to search a file related to NRTcontent. Accordingly, as shown in FIGS. 19 and 20, content_id isinserted into FDT in each file.

Hereinafter, an FDT instance level means, if a common attribute of allfiles declared in FDT needs to be defined, a level including adefinition portion for the common attribute. An FDT file level may meana level including definition for an individual attribute of each file.

A receiver identifies whether a service transmitted through acorresponding channel is an SMT based NRT service. Additionally, thereceiver identifies a content item and file of the corresponding NRTservice.

As mentioned above, although the receiver may identify a file andcontent item in the NRT service, it does not have information on filesof the content item and thus cannot match them. Accordingly, thereceiver may not process the NRT service.

Accordingly, the present invention provides a method of identifyingwhether a content item is related. That is, a corresponding method showswhat kinds of files are included in a content item. In this case, thereceiver may properly process the received NRT service. Accordingly, thecorresponding method may be designated on the basis of FDT informationin FLUTE session transmitting NRT service. For example, each fileconstituting a content item is identified on the basis of acontent-location and TOI field designated in the FLUTE session.content_id in FDT is matched to a content identifier (content_id) of NCTor a content identifier of content fragment in OMB BCAST SG.

Referring to FIGS. 19 and 20, a portion indicated with 1 declares acontent identifier in an FDT-Instance level, and this declared contentidentifier is assigned to all files declared in a correspondingFDT-Instance. Of course, this information may be overridden by assigninga new content identifier in a file level. Or, if a specific file belongsto another content item not a content item defined in the FDT-Instancelevel, this may be notified through assigning a file level content_iddescribed below. This embodiment expresses content_id in 16 bits.

In relation to a portion indicated with 2, when a file in the FDTInstance is included different content items with content_id declarationin a file level, this method signals which file, all files of a contentitem and content, belongs to which entry.

A portion 3 is a method of notifying whether a corresponding file foreach file is an entry file. That is, a file corresponding to a rootfile, which is played first among several files constituting a contentitem or is necessarily executed first to access a content item is calledan entry file, and represents a method of notifying this information. Anentry attribute may be omitted, and its default value is false. When itis omitted, it means that a corresponding file is not an entry file.“Entry” is a head of a file that needs to be processed to execute thefile. For example, “index.html” may be an “entry”. Accordingly, an entryfile may be set with ‘true” and other files are set with “false”.Through the entry file, transmitting the same file repeatedly may beeffectively controlled. Once a file is downloaded, the entry fileindicates a file of content for another reference, so that there is noneed to download it in another or an additional instance.

A specific file functions as an entry in a specific group as a grouprelated to a file level signals whether entry is possible, but itscorresponding role may fail in another group. When a content identifieris assigned in an FDT-instance level, a method of notifying an entryfile may be considered as the following two methods.

1) A method of additionally assigning a file level content identifier toa file corresponding to an entry file and setting its entry attributewith true: in this case, a content identifier is duplicated in anFDT-Instance level and a file level, but has the most flexiblestructure. That is, although one of the File-level and FDT-instancelevel may designate content_id, if another content_id is designatedtogether in the File-level and FDT-instance, the content_id of the Filelevel has priority to that of the FDT-instance level.

2) like another embodiment of the FDT schema of FIG. 20, filesfunctioning as an entry file may be directly referenced in contentidentifier definition in the FDT-instance level. For this, according tothe embodiment of FIG. 20, FDT-Content-ID-Type is additionally definedfor an FDT-instance level content identifier, and as shown in theportion 2, extends to include a content location of an entry file. Inthe case of the portion 2, an entry level is defined with itscontent_id. For example, each content_id shows which entry file exists.

In this method, content-location is duplicated so signaling may beproblematic, but entry file configuration information may be immediatelyobtained by each content item.

FIG. 21 is a flowchart illustrating an operation of a receiver accordingto an embodiment.

Referring to FIG. 21, according to an embodiment, a receiver receivesNRT service signaling data through an NRT service signaling channel,displays NRT guide information on the basis of the received NRT servicesignaling data, and receives NRT service data for the selected NRTcontent, in order to provide NRT service.

First, once the receiver is turned on, a user selects a channel inoperation S1000. Then, a physical transmission channel is turnedaccording to the selected channel.

Then, VCT and PMT are obtained from a broadcast signal received throughthe tuned physical transmission channel in operation S1010. Then, it isconfirmed in operation S1020 whether there is NRT service by parsing theobtained TVCT (VCT). This is confirmed by checking the service_typefield value in a virtual loop of the VCT. For example, if a service_typefield has 0x08, there is NRT service. Moreover, if not 0x08, since acorresponding virtual channel does not transmit the NRT service, aproper operation such as general A/V service may be performed accordingto information in the virtual channel in operation S1111.

Moreover, if it is determined that there is NRT service, since acorresponding virtual channel transmits NRT service, PID(PID=PID_NST)matching to a specific PID(PID_NST) of stream including a well known IPaddress for NRT service signaling channel address is obtained inoperation S1030.

Moreover, the receiver receives a Transport Packet (TP) having the samePID as the obtained PID value (PID_NST) in operation S1040.

Then, the receiver extracts NRT service signaling data including a NRTservice table (NST) from the received TP, or extracts an IP address forthe NRT service signaling channel access from the received TP, in orderto receive NRT service signaling data transmitted in another formatthrough an IP layer in operation S1050.

Then, the receiver obtains channel information on NRT service datatransmission by each NRT service from NST in operation S1060.

Then, the receiver obtains an NRT content table (NCT) including anNRT_channel_id field value identical to a value of Channel_id, anidentifier of the obtained channel information, from the NRT servicesignaling data in operation S1070.

Then, the receiver obtains content information on NRT contentconstituting each NRT service from each field of the obtained NCT inoperation S1080. For example, the content information may include atleast one of content_delevery_bit_rate, content_available_start_time,content_available_end_time and content_title_text( ) fields according toan embodiment of the NCT.

Then, the receiver displays NRT guide information by using contentinformation in operation S1090. A user may select NRT content to use orbe received, from the displayed NRT guide information.

Then, the receiver obtains NRT service access information having theselected NRT content from NST in operation S1100. The NRT service accessinformation may include channel information or IP address informationfor receiving NRT service data, for example.

Moreover, the receiver receives a corresponding NRT content in operationS1110 by using the obtained NRT service access information afteraccessing a channel or server for transmitting NRT service, and performsa proper operation according to the NRT content.

FIGS. 22 and 23 are views illustrating a receiving system receiving,storing, and playing an NRT content for NRT service according to anotherembodiment.

The receiver of FIG. 23 may include an operation controlling unit 100, abaseband processing unit 110, a service demultiplexer 120, a streamcomponent handler 130, a media handler 140, a file handler 150, aservice manager 160, a PVR manager 170, a first storage unit 180, an SGhandler 190, an EPG manager 191, an NRT service manager 192, anapplication manager 194, a middleware engine 193, a presentation manager195, and a User Interface (UI) manager 196.

The baseband processing unit 110 may include a tuner 111 and ademodulator. The service demultiplexer 120 may include an MPEG-2 TPhandler 121, a PSI/PSIP handler 122, an MPEG-2 TP demultiplexer 123, adescrambler 124, and a second storage unit 125.

The stream component handler 130 may include a Packetized ElementaryStream (PES) demodulator 131, an Elementary Stream (ES) demodulator 132,a PCR handler 133, a STC handler 134, a DSM-CC addressable sectionhandler 135, an IP datagram handler 136, a descrambler 137, a UDPhandler 138, a service signaling section handler 138-1, and aConditional Access System (CAS) 139.

The media handler 140 may include an A/V demodulator 141. The filehandler 150 may include an ALC/LCT stream handler 151, a filereconstruction buffer 152, an XML parser 153, an FDT handler 154, adecompressor 155, a third storage unit 156, and a file decoder 157.

In FIG. 23, the tuner 111 tunes a broadcast signal of a desired channelamong broadcast signals received through a terrestrial wave according toa control of the service manager 160, and then down-converts the tunedbroadcast signal into an Intermediate Frequency (IF) signal to output itto the demodulator 112. The tuner 111 may receive real-time stream andnon-real-time stream. The non-real-time stream is called an NRT streamin the present invention.

The demodulator 112 performs automatic gain control, carrier recovery,and timing recovery on a digital IF signal of a pass band inputted fromthe tuner 111, converts the digital IF signal into a baseband signal,and performs channel equalization. For example, when the broadcastsignal is a VSB modulation signal, a VSB demodulation process isperformed for automatic gain control, carrier recovery, and timingrecovery.

The demodulated and channel-equalized data in the demodulator 112 isoutputted to the MPEG-2 TP handler 121 in an MPEG-2 Transport Stream(TS) packet format.

The MPEG-2 TP handler 121 includes an MPEG-2 TP buffer and an MPEG-2 TPparser, and analyzes a TS header after temporarily storing an output ofthe demodulator 112. Then, if an output of the demodulator 112 is an A/VTS packet for real time or an NRT TS packet, it is outputted to thedemultiplexer 123, and if it is a TS packet for PSI/PSIP table, it isoutputted to the PSI/PSIP handler 122.

The PSI/PSIP handler 122 includes a PSI/PSIP section buffer and aPSI/PSIP parser, and after temporarily storing a TS packet outputtedfrom the MPEG-2 TP handler 121, restores and parses a correspondingtable from PSI/PSIP section data in a payload of the TS packet, withreference to a table identifier. At this point, it is determined whetherone table includes one section or a plurality of sections through atable_id field, a section_number field, and a last_section_number fieldin a corresponding section. Also, sections having the same tableidentifier are collected to complete a corresponding table. For example,sections having a table identifier allocated to VCT are collected tocomplete VCT. Moreover, the parsed information of each table iscollected by the service manager 160 to be stored in the first storageunit 180. Table information such as VCT, PAT, PMT, and DST are stored inthe first storage unit through the above processes. The service manager160 stores the table information in the first storage unit 180 in aservice map and guide data format.

The demultiplexer 123, if the inputted TS packet is an A/V TS packet inreal time, divides the TS packet into an audio TS packet and a video TSpacket, and then outputs them into the PES decoder 131. If the inputtedTS packet is an NRT TS packet, it is outputted to the DSM-CC handler135. Additionally, the demultiplexer 123, if the TS packet includes aProgram Clock Reference (PCR), outputs it to the PCR handler 133, and ifit includes Conditional Access (CA) information, outputs it to the CAS139. An NRT TS packet includes a TS packet having NRT service data and aTS packet having NRT service signaling channel. A unique PID foridentifying the NRT service is allocated to a TS packet of the NRTservice data, and PID of a TS packet including the NRT service signalingchannel is extracted using DST and PMT.

The demultiplexer 123, if a payload of the inputted TS packet isscrambled, outputs it to the descrambler 124, and then, the descrambler124 receives information (control words used for scramble) necessary fordescramble from the CAS 139, and performs descramble on the TS packet.

The demultiplexer 123 stores an A/V packet in real time, inputted at theone request of temporary recording, scheduled recording, and time shift,in the second storage unit 125. The second storage unit 125 is a massstorage medium and may include HDD, for example. The second storage unit125 performs downloading (i.e., storing) and updating (i.e., playing)according to a control of the PVR manager 170.

The demultiplexer 123 separates an audio TS packet and a video TS packetfrom the A/V TS packet updated from the second storage unit and thenoutputs them to the PES decoder 131 at the playing request.

The demultiplexer 123 is controlled by the service manager 160 and/orthe PVR manager 170 to perform the above processes.

That is, if a service_type field value in VCT indicates that NRT serviceis transmitted, the service manger 160 extracts identificationinformation of each NRT service from NRT_service_descriptor( ) receivedfrom a virtual channel loop of the VCT and stores it, and then extractsDST PID from a service location descriptor (or an ES loop of PMT) of theVCT to receive DST.

Then, NRT service is identified from the received DST, and PID of anMPEG-2 TS packet including the NRT service signaling channel isextracted to receive the identified NRT service by using DST and PMT.The extracted PID is outputted to the demultiplexer 123. Thedemultiplexer 123 outputs MPEG-2 TS packets corresponding to PID,outputted from the service manager 160, to the addressable sectionhandler 135.

The PCR is a time reference value used for time synchronization of audioES and video ES in the A/V decoder 141. The PCR handler 133 restores PCRin the payload of the inputted TS packet and outputs it to the STChandler 134. The STC handler 134 restores System Time Clock (STC), i.e.,a reference clock of a system, from the PCR, and outputs it to the A/Vdecoder 141.

The PES decoder 131 includes a PES buffer and a PES handler, and aftertemporarily storing an audio TS packet and a video TS packet, removes aTS header from the TS packet to restore audio PES and video PES. Therestored audio PES and video PES are outputted to the ES decoder 132.The ES decoder 132 includes an ES buffer and an ES handler, and removeseach PES header from audio PES and video PES to restore audio ES andvideo ES, i.e., pure data. The restored audio ES and video ES areoutputted to the A/V decoder 141.

The A/V decoder 141 decodes the audio ES and video ES through eachdecoding algorithm to restore a previous state of compression, and thenoutputs it to the presentation manager 195. At this point, timesynchronization is performed when audio ES and video ES are decodedaccording to the STC. As one example, an audio decoding algorithmincludes at least one an AC-3 decoding algorithm, an MPEG 2 audiodecoding algorithm, an MPEG 4 audio decoding algorithm, an AAC decodingalgorithm, an AAC+ decoding algorithm, an HE AAC decoding algorithm, anAAC SBR decoding algorithm, an MPEG surround decoding algorithm, and aBSAC decoding algorithm. A video decoding algorithm includes at leastone of an MPEG 2 video decoding algorithm, an MPEG 4 video decodingalgorithm, an H.264 decoding algorithm, an SVC decoding algorithm, and aVC-1 decoding algorithm.

The CAS 139 includes a CA stream buffer and a CA stream handler, andafter temporarily storing a TS packet outputted from the MPEG-2 TPhandler or service protection data restored and outputted from a UDPdatagram handler 138, restores information (for example, control wordsused for scramble) necessary for descramble from the stored TS packet orservice protection data. That is, Entitlement Management Message (EMM)and Entitlement Control Message (ECM) in the payload of the TS packetare extracted and information necessary for descramble is obtained byanalyzing the extracted EMM and ECM. The ECM may include a control word(CW) used in scramble. At this point, the control word may be encryptedusing an encryption key. The EMM may include an encryption key andqualification information of corresponding data. Information necessaryfor descramble obtained from the CAS 139 is outputted to the descrambler124 and 137.

The DSM-CC section handler 135 includes a DSM-CC section buffer and aDSM-CC section parser, and after temporarily storing a TS packetoutputted from the demultiplexer 123, restores an addressable section inthe payload of the TS packet. After restoring IP datagram by removing aheader and CRC checksum of the addressable section, the restored IPdatagram is outputted to the IP datagram handler 136.

The IP datagram handler 136 includes an IP datagram buffer and an IPdatagram parser. After buffering IP datagram delivered from the DSM-CCsection handler 135, the IP datagram handler 136 extracts and analyzes aheader of the buffered IP datagram to restore UDP datagram from thepayload of the IP datagram, and then, outputs it to the UDP datagramhandler 138.

At this point, if the IP datagram is scrambled, the scrambled UDPdatagram is descrambled in the descrambler 137 and then is outputted tothe UDP datagram handler 138. As one example, the descrambler 137receives information (e.g., a control word used for scramble) necessaryfor descramble from the CAS 138 and performs descramble on the UDPdatagram to output it to the UDP datagram handler 138.

The UDP datagram handler 138 includes an UDP datagram buffer and a UDPdatagram parser. After buffering IP datagram delivered from the IPdatagram handler 136 or the descrambler 137, the UDP datagram handler138 extracts and analyzes a header of the buffered UDP datagram torestore the data included in the payload of the UDP datagram. At thispoint, if the restored data is service protection data, it is outputtedto the CAS 139; if the restored data is NRT service signaling data, itis outputted to the service signaling section handler 138-1; and if therestored data is NRT service data, it is outputted to the ALC/LCT streamhandler 151.

That is, access information on the IP datagram transmitting the NRTservice signaling channel is a well-known destination IP address and awell-known destination UDP port number.

Accordingly, the IP datagram handler 136 and the UDP datagram handler138 include a well-known destination IP multicast address and awell-known destination UDP port number, and extracts an IP multicaststream transmitting an NRT service signaling channel, i.e., NRT servicesignaling data, to output it to the service signaling section handler138-1.

Moreover, the service signaling section handler 138-1 includes a servicesignaling section buffer and a service signaling section parser, andrestores and parses NST from the NRT service signaling data to output itto the service manager 160. When the NST is parsed, access informationof the FLUTE session that transmits content/files constituting NRTservice and signaling information necessary for rendering the NRTservice may be extracted. For example, information necessary forrendering content/files of the NRT service, transmitted from the NST toeach FLUTE session, may be extracted. Information necessary forrendering the content/files of the NRT service may include containerinformation, encoding information, or decoding parameters of a mediaobject.

The parsed information from the NST is collected by the service manager160, and then, stored in the first storage unit 180. The service manager160 stores the extracted information from the NST in the first storageunit 180 in a service map and guide data format. As another example, theNRT service manager 182 may serve as the service manager 160. That is,the parsed information from the NST is collected by the NRT servicemanager 192, and then, stored in the first storage unit 180.

The ALC/LCT stream hander 151 includes an ALC/LCT stream buffer and anALC/LCT stream parser, and after buffering data having an ALC/LCTstructure outputted fro the UDP datagram handler 138, analyzes a headerand header extension of an ALC/LCT session from the buffer data. On thebasis of the analysis result of the header and header extension of theALC/LCT session, if data transmitted to the ALC/LCT session has an XMLstructure, it is outputted to the XML parser 153. If the data has a filestructure, after being temporarily stored in the file reconstructionbuffer 152, it is outputted to the file decoder 157 or stored in thethird storage unit 156. The ALC/LCT stream handler 151 is controlled bythe NRT service manager 192 if data transmitted to the ALC/LCT sessionis data for NRT service. At this point, if data transmitted to theALC/LCT session is compressed, after decompressed in the decompressor155, it is outputted to at least one of the XML parser 153, the filedecoder 157, and the third storage unit 156.

The XML parser 153 analyzes XML data transmitted through the ALC/LCTsession, and if the analyzed data is for a file based service, it isoutputted to the FDT handler 154. If the analyzed data is for serviceguide, it is outputted to the SG handler 190.

The FDT handler 154 analyzes and processes a file description table ofthe FLUTE protocol through an ALC/LCT session. The FDT handler 154 iscontrolled by the NRT service manager 192 if the received file is forNRT service.

The SG handler 190 collects and analyzes data for service guidetransmitted in the XML structure and then output it to the EPG manager191.

The file decoder 157 decodes a file outputted from the filereconstruction buffer 152, a file outputted from the decompressor 155,or a file uploaded from the third storage unit 156 through apredetermined algorithm, thereby outputting it to the middleware engine193 or the A/V decoder 141.

The middleware engine 193 interprets and executes data having a filestructure, i.e., application. Moreover, the application may be outputtedto a screen or speaker through the presentation manager 195. Themiddleware engine 193 is a JAVA based middleware engine according to anembodiment.

The EPG manager 191 receives service guide data from the SG handler 190according to a user input, and then, converts the received service guidedata into a display format to output it to the presentation manager 195.The application manager 194 performs general managements on processingapplication data received in the format such as a file.

The service manager 160 collects and analyzes PSI/PSIP table data or NRTservice signaling data transmitted to an NRT service signaling channelto create a service map, and then stores it in the first storage unit125. Additionally, the service manager 160 controls access informationon NRT service that a user wants, and also controls the tuner 111, thedemodulator 112, and the IP datagram handler 136.

The operation controller 100 controls at least one of the servicemanager 160, the PVR manger 170, the EPG manager 191, the NRT servicemanager 192, the application manager 194, and the presentation manager195 according to a user command, and thus, performs a function that auser wants.

The NRT service manager 192 performs general management on NRT servicetransmitted in a content/file format through the FLUTE session on an IPlayer.

The UI manager 196 delivers a user input to the operation controller 100through UI.

The presentation manager 195 provides to a user through at least one ofa speaker and a screen at least one of audio/video data outputted fromthe A/V decoder 141, file data outputted from the middleware engine 193,and service guide data outputted from the EPG manager 191.

Moreover, one of the service signaling section handler 138-1, theservice manager 160, and the NRT service manager 192 obtains contentconstituting the NRT service or IP access information on the FLUTEsession transmitting a file, from a FLUTE session loop of NST (or an acomponent loop of NST). Additionally, the one obtains FLUTE level accessinformation from component_descriptor( ) received in the component loopof the NST.

Then, the ALC/LCT stream handler and the file decoder 157 access theFLUTE file delivery session by using the obtained FLUTE level accessinformation to collect files in the session. Once the files arecollected, they constitute one NRT service. This NRT service may bestored in the third storage unit 156, or outputted to the middlewareengine 193 or the A/V decoder 141 to be displayed on a display device.

The third storage unit 158, i.e., a storage medium storing a file suchas NRT service data, may be shared with the second storage unit 125, ormay be separately used.

FIG. 24 is a flowchart illustrating a method of a receiver to receiveand provide NRT service according to an embodiment.

The receiver may obtain NRT service signaling information through an NRTservice signaling channel or by receiving IP datagram in the case ofmobile NRT service, and obtains SMT from the NRT service signalinginformation in operation S2010.

Then, the receiver obtains NRT service information from SMT in operationS2020. The NRT service information may be obtained by parsingNRT_service_info_descriptor in a service level descriptor loop. Theobtained NRT service information may include requirement information onan application type for each NRT service or other NRT services.

Later, the receiver outputs NRT service guide on the basis of theobtained NRT service information in operation S2030. The NRT serviceguide may include application and service category information on eachservice. Additionally, detailed information may be further displayed onthe basis of each field of NRT service info descriptor. The detailedinformation may include capacity information on corresponding NRTservice according to a storage requirement field or audio or video codecinformation on corresponding NRT service according to anaudio_codec_type or video_codec_type field. A user may select NRTservice to receive and use it on the basis of the information in theservice guide.

Then, the receiver obtains identifier (content_id) for content itemsconstituting the selected NRT service from NCT in operation S2040. Thereceiver obtains NRT_service_id corresponding to the selected NRTservice from SMT, obtains NCT having the same NRT_channel_id value asthe obtained NRT_service_id, and obtains an identifier (content_id) forcontent items constituting a corresponding NRT service through theobtained NCT.

Then, the receiver accesses the FLUTE session to receive a fileconstituting the corresponding content item by using the obtainedcontent item identifier (content_id) in operation S2050. Since each fileconstituting the content item is matched to TOI or a content locationfield of FDT in the FLUTE session, the receiver receives a file of acorresponding content item by using the FLUTE session in operationS2060. The receiving of the file may include receiving a correspondingfile or object when a Content-ID attribute field for a correspondingfile is identical to the obtained content_id after reading FDT in acorresponding FLUTE session.

Additionally, the receiver parses FDT instances in a corresponding FLUTEsession to obtain a list of files corresponding to the content item.Moreover, the receiver obtains entry information including a list offiles serving as an entry among lists of files.

Lastly, the receiver provides NRT service to a user on the basis of thereceiver content item and the list of files corresponding thereto orentry information in operation S2080.

The content downloaded through the NRT service may be used at the timingthat a user wants, being separated from real-time broadcasting.

Additionally, after transmitting NRT service in advance and storing itin a receiver, a broadcasting station may designate a content item ofthe corresponding NRT service, which is executed at the timing of when aspecific real-time broadcasting is transmitted or the NRT service isdisplayed. According to an embodiment of the present invention, the NRTservice may include content, which is downloaded in advance linking withreal-time broadcasting and executed at the specific timing.Additionally, according to an embodiment of the present invention, theNRT service may include content, which is prepared in advance to executespecific NRT service at the specific timing. An NRT service contenttriggered at the specific timing linked with real-time broadcasting toexecute a specific action for a specific NRT service is called aTriggered Declarative Object (TDO). Accordingly, an NRT serviceapplication is classified as a non-real time declarative object (NDO) ora triggered declarative object (TDO) according to whether it is executedat the specific timing.

According to an embodiment of the present invention, a broadcastingstation may transmit trigger information on trigging the TDO. Thetrigger information may include information on performing a specificaction for a specific TDO at the specific timing.

Additionally, the trigger information may include trigger signaling data(trigger signaling information) for signaling a trigger, and triggerdata constituting a trigger. Additionally, data stream transmittingtrigger data may be designated as trigger stream. Also, the trigger datamay mean itself.

Such a trigger may include at least one of a trigger identifier foridentifying a trigger, a TDO identifier for identifying NRT service fortrigger, and action information and trigger time on TDO.

The trigger identifier may be an identifier uniquely identifying atrigger. For example, a broadcasting station may include at least onetrigger in broadcasting program information of a predetermined timeprovided through EIT. In this case, the receiver may perform an actionon the trigger target TDO at the timing designated for each trigger onthe basis of at least one trigger. At this point, the receiver mayidentify each trigger by using a trigger identifier.

A TDO identifier may be an identifier for identifying an NRT servicecontent, i.e., a target of trigger. Accordingly, the TDO identifier mayinclude at least one of a trigger NRT service identifier(NRT_service_id), content linkage (content_linkage), and URI or URL ofan NRT content item entry. Moreover, the TDO identifier may include atarget identifier (target_service_id) for identifying a trigger targetTDO described later.

Additionally, TDO action information may include information on actionfor TDO of a trigger target. The action information may be at least oneof execution, termination, and extension commands of the target TDO.Additionally, the action information may include commands for generatinga specific function or event in the target TDO. For example, if theaction information includes the execution command of the target TDO, atrigger may request the activation of the target TDO to the receiver.

Additionally, if the action information includes the extension commandof the target TDO, a trigger may notify the receiver that the target TDOwould extend. Additionally, if the action information includes thetermination command of the target TDO, a trigger may notify the receiverthat the target TDO would terminate. Thus, the broadcasting station maycontrol a TDO operation in the receiver according to a real-time contentthrough trigger.

Moreover, a trigger time may mean a time designated for performing(trigging) an action designated for the target TDO. Additionally, thetrigger time may be synchronized with video stream in a specific virtualchannel in order to link NRT service with real-time broadcasting.Accordingly, the broadcasting station may designate a trigger time withreference to PCR that video stream refers. Accordingly, the receiver maytrigger TDO at the timing that the broadcasting station designates withreference to PCR that video stream refers. Moreover, the broadcastingstation may signal a trigger with a trigger identifier in a header ofvideo stream in order to transmit accurate trigger time.

Additionally, the trigger time may be designated with UTC time. In thecase of UTC time, the trigger time is not a relative time but anabsolute time.

The trigger time may be accurate trigger timing or may include anapproximate start time. Moreover, the receiver may prepare an action fortarget TDO in advance before accurate trigger timing by receivingapproximate time. For example, the receiver may prepare TDO execution inadvance so that TDO operates smoothly at the trigger time.

FIG. 25 is a view illustrating a bit stream syntax of a triggeraccording to an embodiment.

Here, trigger or trigger data is in a trigger table form, and acorresponding syntax is in an MPEG-2 private section form to helpunderstanding. However, the format of corresponding data may vary. Forexample, the corresponding data may be expressed in a SessionDescription Protocol (SDP) format and signaled through a SessionAnnouncement Protocol (SAP) according to another method.

A table_id field is set with 0XTBD arbitrarily, and identifies that acorresponding table section is a table section constituting a trigger.

A section_syntax_indicator field is set with 1 and indicates that thesection follows a general section syntax.

A private_indicator field is set with 1.

A section_length field describes that the number of bits remaining inthe section to the last of the section from immediately after thesection_length field.

A source_id field represents the source of a program related to avirtual channel.

A TTT_version_number field represents version information of a trigger.Additionally, the version information of a trigger represents theversion of a trigger protocol. The trigger version information may beused for determining where there is change in a trigger structure or atrigger itself. For example, the receiver determines that there is notrigger change if the trigger version information is identical.Additionally, the receiver determines that there a trigger change if thetrigger version information is different. For example, the triggerversion information may include a plurality of version numbers, and thereceiver may determine whether there is a trigger change on the basis ofsome of the plurality of version numbers.

A current_next_indicator field represents that a corresponding tablesection is applicable currently if set with 1.

A section_number field indicates a number of a corresponding tablesection.

A last_section_number field means a table section of the last andhighest number among sections.

A num_triggers_in_section field means the number of triggers in acorresponding table section. The number of triggers in one session maybe one or in plurality. Additionally, the next ‘for’ loop is performedas many times as the number of triggers.

A trigger_id field represents an identifier uniquely identifying atrigger.

A trigger_time field represents a time for which a trigger is performed.Moreover, this field may not be included in the session, and in thiscase, the trigger time may be a time designated from broadcasting streamas mentioned above.

A trigger_action field represents action information of a triggerperformed at the trigger time. A trigger action may include at least oneof a preparation command for target TDO, a target TDO execution command,a target TDO extension command, and a target TDO termination command.The trigger action may further include a command generating a specificcommand or event.

A trigger_description_length field represents the length oftrigger_description_text.

A trigger_description_text field represents description for acorresponding trigger in a text format.

A service_id_ref field represents an identifier identifying a target TDOof a trigger. Accordingly, for example, a service_id_ref field mayindicate an NRT_service_id field of SMT or NST to identify NRT serviceof a trigger target TDO.

A content_linkage field represents an identifier identifying a targetTDO content item of a trigger. For example, a content_linkage field mayindicate a content_linkage field of NRT-IT or NCT to identify a targetTDO content item of a trigger. Additionally, a service_id_ref field anda content_linkage field may be included in a class for indicating onetarget TDO.

A num_trigger_descriptors field represents the number of triggerdescriptors.

A trigger_descriptor( ) field represents a descriptor includinginformation on a trigger.

When a trigger is in a table format of the MPEG-2 private section, abroadcasting station may transmit one trigger according to a virtualchannel.

A first method of a broadcasting station to transmit a trigger mayinclude transmitting 0X1FF stream including the trigger table, i.e.,PSIP basic PID. The first method may distinguish the trigger table fromother tables by allocating table_id of the trigger table.

Moreover, a second method of transmitting a trigger includes allocatingPID corresponding to a trigger table to a Master Guide Table (MGT) andtransmitting a corresponding PID stream having the trigger table. Thesecond method processes all tables in a corresponding PID stream byusing the trigger table.

Moreover, according to an embodiment, at least one of trigger andtrigger signaling information is transmitted through an MPEG-2Packetized Elementary Stream (PES) in order to designate the accuratetiming synchronized with video and audio as a trigger time.

Here, the video and audio synchronization of MPEG-2 PES will bedescribed as follows. A receiver decoder operates in synchronizationwith a time stamp of a transmitter encoder. The encoder has a mainoscillator, called a System Time Clock (STC), and a counter. The STC isincluded in a specific program and a main clock of program for video andaudio encoders.

Moreover, if a video frame or an audio block occurs in an encoder input,STC is sampled. A sampling value and a constant value as much as delayof the encoder and decoder buffers are added to generate display timeinformation, i.e., Presentation Time Stamp (PTS) and then are insertedinto the first portion of a picture or audio block. When framereordering occurs, Decode Time Stamp (DTS) representing a time at whichdata needs to be decoded in a decoder is inserted. Except for the framereordering of the B picture, DTS and PTS are same. DTS is additionallyrequired in the case of the frame reordering. When DTS is used, there isPTS always. They may be inserted at an interval of less than about 700msec. Additionally, it is defined in ATSC that PTS and DTS are insertedat the starting portion of each picture.

Moreover, an output of an encoder buffer includes a time stamp such asProgram Clock Reference (PCR) in a transport packet level. Moreover, aPCT time stamp occurs at an interval of less than 100 msec, and is usedfor synchronizing STC of a decoder and STC of an encoder.

Moreover, video stream and audio stream may have each PTS or DTScorresponding to a common STC, for synchronization of audio stream andthe decoder. Accordingly, PTS and DTS indicate when audio stream andvideo stream are played at each decoding unit, and are used tosynchronize audio and video.

For example, a decoder of receiver outputs a PES packet in the receivedTS stream as a video PES depacketizer, and outputs a PCR value insertedin a TS packet header to a PCR counter. The PCR counter counts 100 ofthe PCR value and outputs it to a comparison unit. Moreover, the videoPES depacketizer outputs a header of a PES packet to a DTS/PTSextractor, buffers Elementary Stream, i.e., image data to be displayed,in an Elementary Stream Buffer&Decoder. The DTS/PTS extraction unitextracts DTS and PTS values from the PES packet header and outputs themto the comparison unit. The comparison unit, if the PCR value inputtedfrom the PCR counter becomes a DTS value or the PCR value of 100 becomesa PTS value, outputs each signal for that to a decoding/display controlunit. The decoding/display control unit receives a signal that the PCRvalue becomes the DTS value from the comparison unit, and decodes theimage data buffered in the elementary stream buffer & decoder to storethem in a decoded stream memory. Additionally, the decoding/displaycontrol unit displays the decoded image data stored in the decodedstream memory through a display unit when receiving the signal that thePCR value becomes the PTS value from the comparison unit

Accordingly, MPEG-2 PES includes PTS and DTS in its header, whichsynchronize data transmitted during data transmission with oneelementary stream (ES) or presentation time between a plurality of ES.This is called a synchronized data stream method.

That is, according to an embodiment, a broadcasting station includestrigger data or trigger stream in the payload of PES and designatestrigger time as a PTS value of the PES packet header by using the abovesynchronized data stream method. In this case, the receiver may triggera target TDO at the accurate timing according to the PCR value that PTSof PES including a trigger refers. Accordingly, a broadcasting stationmay synchronize a trigger at the accurate timing of audio and videopresentation that the broadcasting station is to trigger by using thePTS of the PES packet header designated as a trigger time and the PTS ofthe audio and video PES packet header.

Moreover, in relation to the header of the PES stream packet including atrigger, a stream_type value may be 0x06 to indicate a synchronized datastream method, stream_id may indicate a identifier of a predeterminedstream, and PES_packet_length may indicate the length of PES streamincluding the payload of PES stream.

FIG. 26 is a view illustrating a PES structure according to asynchronized data stream method including a trigger according to anembodiment.

As shown in FIG. 26, PES of the synchronized data stream method mayinclude a PES header and PES payload. The PES payload may include asynchronized data packet structure. As mentioned above, the triggerincluding a trigger table or another type of data may be included in thePES payload of FIG. 26 and then transmitted. Additionally, abroadcasting station may packetize the trigger in an IP datagram format,and may include and transmit the packetized trigger in an IP data area.

FIG. 27 is a view illustrating a synchronized data packet structure ofPES payload for transmitting trigger as bit stream syntax according toan embodiment.

As shown in FIGS. 26 and 27, the trigger may be included in thesynchronized data packet structure and then transmitted. Detaileddescription of each field in the structure is as follows.

A data_identifier field is an identifier identifying a type of dataincluded in a PES data packet. This may be set with 0X22 according to atype.

A sub_stream_id field is an identifier (user private) settable by auser.

A PTS_extention_flag field indicates whether there is a PTS_extentionfield. If this field value is 1, the PTS_extension field may be in thePES_data_packet field. Additionally, this field may be 0 when there isno PTS_extension field.

An output_data_rate_flag field may be set with 0.

A syncnronized_data_packet_header_length field represents the length ofan optical field in the PES packet header. This field may be included Ifthe PTS_extention_flag field is 1, and represents the length includingsynchroziced_data_privete_data_byte(s).

A PTS_extension field extends PTS delivered from the header of acorresponding PES packet. This field may include 9 bit Program ClockReference (PCR) extension information. Additionally, a receiver mayextend the PTS resolution of synchronized data from 11.1 μs (90 kHz),i.e., the MPEG-2 standard, to 37 ns (27 MHz).

A synchronized_data_private_data_byte field represents a payload byte ofa synchronized PES packet. If the protocol_encapsulation of DSTrepresents one of synchronized datagram, IP datagram not includingLLC/SNAP, and multiprotocol including LLS/SNAP, thesynchronized_data_byte field may include one unique datagram.Accordingly, when LLC/SNAP is used, an 8 byte LLC/SNAP header may beshown in only the first 8 byte synchronized_data_byte of the PES packet.

Accordingly, if a broadcasting station includes a trigger in asynchronized data stream (stream_type) of PES and transmits it, areceiver may extract trigger stream from the payload of PES.Additionally, the receiver may perform an action on a target TDO byusing the PTS value of the PES header as a trigger time. Accordingly,TDO may be trigged at the accurate timing of a frame unit bysynchronizing a trigger on the basis of PTS, i.e., a reference time forpresentation synchronization of video and audio. Additionally, when atrigger time is designated with PTS, video and audio synchronization maybe easily obtained.

Moreover, trigger signaling information on obtaining trigger stream istransmitted according to an embodiment. A receiver receives triggersignaling information and obtains trigger stream in the synchronizeddata stream of PES on the basis of the received trigger signalinginformation.

A method of transmitting trigger signaling information to obtain triggerstream transmitted using synchronized data streaming may vary. One ofthe following methods is used to transmit trigger signalinginformation: 1. a transmission method through DST; 2. a transmissionmethod through a service id descriptor; 3. a transmission method througha trigger stream descriptor; and 4. a transmission method by defining astream type of trigger stream.

According to an embodiment, trigger signaling information may betransmitted through DST for NRT service. DST is a table session fortransmitting data service. Since its description and description for itsdata_service_bytes( ) are identical to those of FIG. 8, overlappingdescription will be omitted.

The DST may include signaling data for receiving each Elementary Stream(ES) constituting data service. Accordingly, trigger signaling data forreceiving trigger stream may be included in DST.

Moreover, each data service may include at least one application, andeach application may in an application identification structureincluding an application identifier such as app_id. Moreover, eachapplication may include at least one data element constituting acorresponding application or data stream.

Accordingly, in order to transmit trigger stream through data service, abroadcasting station includes one trigger stream in a specific virtualchannel and transmits it. Moreover, the broadcasting station may includeone trigger stream in each application and transmit it. Accordingly,embodiments for transmitting trigger signaling information will bedescribed according to two methods.

When one trigger stream is included a virtual channel, a data servicefor transmitting trigger stream is called a trigger service. In thiscase, a broadcasting station may allocate a fixed service identifier(service ID) to a trigger service.

Accordingly, a receiver may identify that one trigger stream istransmitted to a virtual channel when the service identifier has 0X01 asa fixed value.

Here, the broadcasting station may include trigger signaling informationin an application identification structure in DST and transmit it.

For example, the broadcasting station adds 0x0001 as anApp_id_description field value of DST to set a value that meansinteractive application for linking NT service such as TDO with areal-time broadcast Additionally, app_id_byte_length may use 3 bytes(0x0003) and app_id_byte may be allocated with 0x01 to indicate thatcorresponding data service includes trigger stream signalinginformation.

Accordingly, the receiver receives DST through the above method, and mayidentify tap( ) including trigger signaling information whenapp_id_byte_length is 0x0003, app_id_description is 0x0001, andapp_id_byte is 0x01. The receiver extracts trigger signaling informationincluding an association_tag value from the identified tap( ) structure,and association_tag_descriptor receives stream having the same PID asthe extracted association_tag from data elementary stream (ES) listed inPMT extracted from broadcasting stream in order to receive triggerstream.

As mentioned above, NRT service is signaled through SMR or NST, and maybe uniquely identified through 16 bit service identifier (sevice_id).Additionally, content items constituting NRT service may be identifiedthrough conent_lengate or a content identifier in NCT or NRT-IT.Accordingly, trigger service may be transmitted like NRT service byextending app_id_byte through DST. For example, app_id_byte may includedata combining a service identifier (service id) field of triggerservice and a content_linkage field. Accordingly, the first 16 bits ofapp_id_byte correspond to a service id field in SMT or NST, and thelater 32 bits correspond to a content linkage field in NCT or NRT-IT.

As above, the broadcasting station may include trigger signalinginformation in tap( ) and transmits it through an applicationidentification structure of DST when one stream is included in eachchannel.

Moreover, according to an embodiment, trigger signaling information maybe transmitted through a protocol_encapsulation field of DST. Forexample, if app_id_byte_length in DST is set with 0x0000, app id is notallocated. If protocol_encapsulation has 0x0F, it indicates that triggersignaling information is included in a corresponding tap( ) structure.Accordingly, a receiver may receive trigger signaling information fromthe corresponding tap( ) structure if app_id_byte_length is 0x0000 andprotocol_encapsulation is 0x0F. Through this, a PID value on PMTindicating trigger stream is obtained and trigger stream is received asmentioned above.

Moreover, according to another embodiment, trigger signaling informationmay be transmitted through a content type descriptor field of DST.

As shown in FIG. 28, a content type descriptor structure in tap( ) onDST according to an embodiment is as follows.

A descriptorTag may have 0x72 to represent contentTypeDescriptor.

A descriptorLenth field represents the total length of a descriptor in abyte unit.

A contentTypeByte field represents a MIME media type value of datareferenced by tap connected to the descriptor. The MIME media type isdefined in 5 of RFC2045 section [8].

Accordingly, a content type descriptor may be added to a tap( )structure including trigger signaling information according to anembodiment. Accordingly, a receiver may receive trigger signalinginformation from the corresponding tap( ) structure ifapp_id_byte_length is 0x0000 and content type descriptor of the tap( )structure corresponds to the predetermined content. Through this, a PIDvalue on PMT indicating trigger stream is obtained and trigger stream isreceived as mentioned above. The MIME media type may be designated witha specific type to identify that there is trigger service signalinginformation through a content type descriptor.

As mentioned above, one NRT service may be a trigger service fortransmitting trigger stream and may transmit respectively differentstream to content items in the trigger service. In this case, eachapplication may include one trigger stream.

Accordingly, an embodiment may include trigger stream in each contentitem of NRT service and may transmit it. In this case, theabove-mentioned application identification structure may be used. Forexample, if app_id_byte_length is 0x0003, it indicates that triggerstream is transmitted through one NRT service by using one serviceidentifier. If app_id_byte_length is 0x0007, it indicates that triggerstream is transmitted by each content item by using a service identifierand content linkage. If defined as above, each trigger stream may betransmitted in correspondence to each NRT service or content item. Sincethe next stage of a method of transmitting and receiving trigger streamis identical to that of transmitting one trigger stream for each virtualchannel, overlapping description will be omitted.

FIG. 29 is a view illustrating a syntax of PMT and service identifierdescriptor according to an embodiment.

As shown in FIG. 29, a Program Map Table (PMT) represents information ofa program broadcasted in each channel. A Program AssociationTable (PAT),in which ‘packet ID’ is defined as ‘0x00’ and transmitted, may receivePMT by parsing ‘packet ID’ of PMT.

Moreover, a service identifier descriptor may be included in adescriptor loop for each ES of PMT. Then, it may include listinformation of services in each program element.

A structure of the service identifier descriptor will be described asfollows.

A descriptor_tag field indicates that the descriptor isservice_id_descriptor( ) and may have 0xC2.

A descriptor_length field represents a byte unit length from this fieldto the termination of the descriptor.

A service_count field indicates the number of services in a programelement having the descriptor.

A service_id field indicates a service identifier in a program elementhaving the descriptor.

According to an embodiment, trigger stream may be transmitted through awell-known IP address. Moreover, in order to signal a trigger, abroadcasting station may include a specific service identifier (serviceid, for example, 0x01) corresponding trigger stream in a serviceidentifier descriptor and may transmit it. That is, trigger signalinginformation on receiving trigger stream may be transmitted through aservice identifier descriptor. Accordingly, if a service identifier ofservice_id_descriptor in an ES descriptor loop in an ES loop of PMT is0x01, the receiver determines that elementray_PID in the ES loop is PIDindicating trigger stream and receives the trigger stream through thePID.

FIG. 30 is a view illustrating a trigger stream descriptor according toan embodiment. According to an embodiment, a trigger may be signaledusing a trigger stream descriptor. Like the above service identifierdescriptor, the trigger stream descriptor may be included in an ESdescriptor loop in an ES loop of PMT. Accordingly, if there is triggerstream, a trigger stream descriptor may exist in an ES descriptor loop.If identifying a trigger stream descriptor, a receiver may receivetrigger stream by obtaining PID of the trigger stream fromelementary_PID in a corresponding ES loop.

Like this, a trigger stream descriptor for transmitting triggersignaling information may include at least one of a service identifier(target service id) of TDO, a trigger target in trigger stream, and anIP address list transmitting trigger stream. The trigger streamdescriptor of FIG. 30 is provided according to an embodiment and itsstructure will be described as follows.

A descriptor_tag field indicates a trigger_stream_descriptor if set witha predetermined value.

A descriptor_length field represents a byte unit length from this fieldto the termination of the descriptor.

A target_service_count field represents the number of target NRT service(TOD) of at least one trigger in trigger stream.

A target_service_id field represents a service identifier (service_id)of target NRT service (TOD) of at least one trigger in trigger stream. Areceiver may identify a service identifier (service_id) before receivingtrigger stream by using the target_service_id field.

A target_content_item_count field represents the number of target NRTservice content items of at least one trigger in trigger stream.

A target_content_linkage field represents a target NRT service contentitem linkage (content_linkage) of at least one trigger in triggerstream.

Moreover, a trigger stream descriptor is provided according to anembodiment, and thus, it is apparent that it may include additionalinformation or have another configuration. For example, when one triggerstream is transmitted for each channel, a content item field may beomitted. Additionally, at least one of a trigger stream identificationinformation field and a profile information field may be added toidentify trigger stream.

A broadcasting station may transmit list information of trigger targetNRT service such as TDO by using the trigger stream descriptor.Additionally, the broadcasting station may transmit trigger signalinginformation by using the target_service_id and targe_content_linkagefields if there is another trigger according to a content item.Additionally, a trigger stream descriptor may further include a list ofIP address information or port numbers transmitting trigger stream.

According to an embodiment, a broadcasting station designates a streamtype and transmits trigger signaling information. A receiver extractstrigger signaling information by using a stream type from PMT andreceives trigger stream through the trigger signaling information. Forexample, 0x96, one of stream types set preliminarily at the present, maybe designated as trigger stream. In this case, a typical receiver has noinformation that a stream type is 0x96 and thus may not process triggerstream and disregard it. Accordingly, backwards compatibility for submodel receiver is guaranteed.

According to an embodiment, a trigger may be included in an Applicationinformation Table (AIT) for transmitting application information in databroadcasting such as Multimedia Home Platform (MHP) or Advanced Commonapplication platform (ACAP), and may be transmitted. FIG. 31 is a viewof AIT according to an embodiment.

Moreover, according to another embodiment a trigger may be included in adescriptor of STT to refer to a System Time Table (STT) as a triggertime, and then transmitted. FIG. 32 is a view of STT according to anembodiment.

FIG. 33 is a block diagram illustrating a transmitter for transmittingTDO and a trigger according to an embodiment.

Referring to FIG. 33, the transmitter 200 includes an NRT servicetransmitting unit 210, a trigger transmitting unit 220, a multiplexingunit 230, and a demodulation unit 240. The NRT service transmitting unit210 includes an NRT service (TDO) generating unit 211 and an NRT servicesignaling data generating unit 212. The trigger transmitting unit 220includes a trigger generating unit 221 and a trigger signaling datagenerating unit 222.

The NRT service (TDO) generating unit 211 receives data for NRT servicegeneration from a service provider to generate the NRT service,packetizes the generated NRT service into IP datagram, and thenpacketized the packetized IP datagram into a transmission packet (TP).The packetized NRT service data is transmitted to the multiplexing unit230.

The NRT service generating unit 211 transmits metadata including channelinformation about NRT service in transmission and service_id, to the NRTservice signaling data generating unit 212. Additionally, if thegenerated NRT service is TDO, the NRT service generating unit 211extracts trigger information including a trigger time for triggeringTDO, identification information, and trigger action information of atarget TDO, and then transmits it to the trigger generating unit 221.

The NRT service signaling data generating unit 212 generates NRT servicesignaling data for receiving NRT service by using the NRT servicemetadata, and packetizes the generated NRT service signaling data to thetransmission packet (TP) to transmit it to the multiplexing unit 230.

Additionally, the trigger generating unit 221 generates trigger data byusing trigger information of the TDO received from the NRT service (TDO)generating unit. The generated trigger data is packetized into atransmission packet to transmit it to the multiplexing unit 230.Moreover, the trigger generating unit 221 transmits metadata forreceiving a trigger such as the packet identifier (PID) of thetransmitted trigger data to the trigger signaling data generating unit222.

The trigger signaling data generating unit 22 generates triggersignaling data on the basis of the received metadata, and packetizes thetrigger signal in data into a transmission packet to transmit it to themultiplexing unit 230.

The multiplexing unit 230 multiplexes the received transmission packetsby each channel, and then transmits the multiplexed signal to themodulation unit 240.

The modulation unit 240 modulates the multiplexed signal and transmitsit to the external. The modulation method may vary, and the presentinvention is not limited thereto.

FIG. 34 is a block diagram illustrating a receiver for receiving TDO anda trigger according to an embodiment.

Referring to FIG. 34, the receiver 300 includes a demodulation unit 310,a demultiplexing unit 320, a trigger processing unit 330, an NRT serviceprocessing unit 340, and a service manager 350. The trigger processingunit 330 includes a trigger receiving unit 331 and a trigger signalingdata receiving unit 332. The NRT service processing unit 340 includes anNRT service (TDO) receiving unit 341 and an NRT service signaling datareceiving unit 342.

The demodulation unit 310 receives a modulated signal from thetransmitter 200, and demodulates the received signal according to apredetermined demodulation method to transmit it to the demultiplexingunit 320.

The demultiplexing unit 320 demultiplexes the demodulated signal torestore an original transmission packet for each channel to transmitthem to each receiving unit of the trigger processing unit 330 or theNRT service processing unit 340.

The NRT service signaling data receiving unit 342 receives and restoresthe packetized NRT service signaling data from the multiplexing unit 320to extract information on NRT service, and then transmits it to the NRTservice (TDO) receiving unit 341. The NRT service (TDO) receiving unit341 receives transmission packets of NRT service from the multiplexingunit 320 by using information on receiving NRT service, and restores itas service data to transmit it to the service manager 350.

Moreover, the NRT service signaling data receiving unit 332 receives andrestores the packetized trigger signaling data from the multiplexingunit 320, extract information on receiving a trigger, and then,transmits it to the trigger receiving unit 331. The trigger receivingunit 331 receives transmission packets including a trigger from themultiplexing unit 32 by using information on receiving a trigger, andrestores trigger data to transmit it to the service manager 350.

The service manager 350 receives at least one of trigger data or NRTservice (TDO) data from the trigger processing unit 330 or the NRTprocessing unit 340. Moreover, the service manager 350 performs andapplies a trigger action on a trigger target TDO at the trigger timing,so that a trigger action on TDO is performed.

FIG. 35 is a flowchart illustrating a trigger transmitting methodaccording to an embodiment.

Referring to FIG. 35, the NRT service generating unit 211 generates NRTservice data by receiving NRT service data from external or on the basisof data received from the NRT service provider in operation S100.Moreover, the NRT service generating unit 211 packets the generated datainto a transmission packet. Additionally, the NRT service generatingunit 211 transmits information on receiving transmission packetsincluding NRT service to the NRT service signaling data generating unit212.

Then, the NRT service signaling data generating unit 212 generates theabove described NRT service signaling data and packetizes it into atransmission packet in operation S110.

Moreover, the NRT service generating unit 211 determines whether thegenerated NRT service is a trigger declarative object, i.e., TDO inoperation S120.

Additionally, if the generated NRT service is TDO, the NRT servicegenerating unit 211 transmits trigger information including a triggertime for triggering TDO, trigger action, target TDO identificationinformation, to the trigger generating unit 221, and the triggergenerating unit 211 generates trigger data by using the receivedtriggered information in operation S130. The generated trigger data ispacketized into a transmission packet and transmitted to themultiplexing unit. For example, a target service identifier for targetTDO and trigger action information applied to a target service may beinserted into a packetized stream, i.e., the payload of PES, and thentransmitted. Additionally, trigger time information is designated into aPTS or DTS format, inserted into the payload or header of PES, and thenis transmitted. When the synchronized data streaming method is used, PTSof trigger stream and PTS of video and audio stream are synchronized toset the accurate play timing.

Moreover, the trigger signaling data generating unit 222 generatestrigger signaling data for identifying and receiving a triggertransmitted from the trigger generating unit 221 and packetized thegenerated trigger signaling data into a transmission packet to transmitit to the multiplexing unit in operation S140. Here, the triggersignaling data may include a trigger stream descriptor or a serviceidentifier descriptor, inserted in a program map table, and may includea packet identifier of trigger stream corresponding to each descriptor.Additionally, trigger signaling data may include a packet identifier oftrigger stream in a TAP structure of DST.

Later, the multiplexing unit 230 multiplexes at least one oftransmission-packetized NRT service data, NRT service signaling data,trigger data, and trigger signaling data by each transmission channeland then transmits it to the modulation unit 240.

Moreover, the modulation unit 240 performs modulation to transmit themultiplexed signal and transmits it to external receiver or abroadcasting network in operation S160.

FIG. 36 is a flowchart illustrating an operation of a receiver 300according to an embodiment.

First, when the receiver 300 is turned on, a channel is selected by auser or a predetermined channel is selected in operation S200. Thedemodulation unit 310 demodulates the received signal from the selectedchannel, and the demultiplexing unit 320 demultiplexes the demodulatedsignal by each transmission channel. Also, the NRT service receivingunit 341 and the NRT service signaling data receiving unit 342 receiveNRT service data and transmit it to the service manager 350 as describedabove.

Then, the trigger signaling data receiving unit 332 or the NRT servicesignaling data receiving unit 342 confirms whether trigger reception ispossible in operation s220. The trigger reception confirmation may useone of the above-mentioned methods. That is, the trigger signaling datareceiving unit 332 or the NRT service signaling data receiving unit 342uses one of a method of confirming PID corresponding to a trigger in MGTor PSIP based PID, a method of using a tap structure of DST, a method ofusing a service identifier descriptor or a trigger stream descriptor, amethod of using a trigger stream type, and a method of using AIT or STT,in order to confirm whether trigger reception is possible.

Moreover, when it is confirmed that trigger reception is possible, thetrigger signaling data receiving unit 332 receives a transmission packetincluding trigger signaling data to restore the trigger signaling data,and then transmits it to the trigger receiving unit 331 in operationS230.

Later, the trigger receiving unit 331 extracts trigger data from thereceived transmission packet by using the trigger signaling data, andtransmits it to the service manager 350 in operation S240. For example,the trigger receiving unit 331 may receive trigger stream by using apacket identifier corresponding to the trigger stream descriptor.Additionally, the trigger receiving unit 331 extracts triggerinformation from trigger stream and transmits it to the service manager350. Additionally, if the received trigger stream is PES, PTS in theheader of PES is extracted as a trigger time, and a target serviceidentifier and trigger action in the payload of PES are extracted, inorder to transmit them to the service manager 350.j

Moreover, the service manager 350 performs a trigger action on a targetTDO at the trigger timing, so that a trigger action on TDO is performedin operation S250. Especially, if the PTS of PES is a trigger time, thePTS of trigger stream is synchronized with the PTS in the header ofaudio and video stream, to satisfy the accurate play timing.

FIG. 37 is a flowchart illustrating a trigger receiving method by usinga trigger table according to an embodiment.

The demodulation unit 310 receives and demodulates a broadcast signalfor selected channel. Moreover, the trigger signaling data receivingunit 332 receives a PSIP table through the demultiplexing unit 320 anddetermines whether there is a trigger table in the received table toidentify a trigger service in operation S310. The trigger signaling datareceiving unit 332 searches PID allocated to a trigger table from an MGTor PSIP based table, or searches a table corresponding to Table_idallocated to a trigger table to identify a trigger service.

If the trigger service is not identified, the receiver 300 providesgeneral broadcasting services.

Moreover, if the trigger service is identified, the trigger receivingunit 331 receives the searched trigger table and parses it in operationsS320 and S330.

Then, the service manger 350 receives trigger information includingtrigger time, trigger action, and target TDO identification informationparsed in the trigger table, and performs a corresponding trigger actionon a corresponding TDO at the corresponding trigger timing in operationS340.

FIG. 38 is a flowchart illustrating an operation of a receiver 300 whentrigger signaling information and trigger are transmitted using DSTaccording to an embodiment.

When a physical transmission channel is selected in operation S3000 anda channel selected by a tuner is tuned, the receiver 300 obtains VCT andPMT from a broadcast signal received through the tuned physicaltransmission channel by using the demodulation unit 310 and thedemultiplexing unit 320 in operation S3010. Then, the PSI/PSIP sectionhandler or the trigger signaling data receiving unit 332 or the NRTservice signaling data receiving unit 342 parses the obtained VCT andPMT to confirm whether there is NRT service.

For example, when the service_type field value of VCT is not 0x04 or0x08, since the corresponding virtual channel does not transmit NRT onlyservice, the receiver 300 operates properly according to information inthe virtual channel. However, even though the service_type field valuedoes not mean NRT only service, the corresponding virtual channel mayinclude NRT service. This case is called adjunct NRT service included inthe corresponding virtual channel, and the receiver 300 may perform thesame process as the case of receiving NRT service.

Then, the NRT service signaling data receiving unit 342 or the triggersignaling data receiving unit 332 determines that NRT service isreceived through a corresponding virtual channel if a service_type fieldvalue is 0x04 or 0x08. In this case, if a stream_type field value in aservice location descriptor of VCT (or an ES loop of PMT) is 0x95 (i.e.,DST transmission), DST is received using an Elementary_PID field valuein operation S3020. This may be performed in the demultiplexing unit 320according to a control of the service manager 350.

Also, the trigger signaling data receiving unit 342 identifies a triggerservice from the received DST in operation S3040. A method ofidentifying a trigger service uses one of a method of identifying aspecific value allocated to app_id_description and app_id_byte by usingan application identification structure, a method of identifying aspecific value allocated to a protocol_encapsulation field, and a methodof identifying tap including a content type descriptor.

If the trigger service is not identified from the received DST, sincetrigger data transmits general NRT service through a correspondingvirtual channel, the receiver 300 operates properly according to NRTservice in the corresponding virtual channel in operation S3030.

Moreover, when the trigger service is identified from DST, the triggersignaling data receiving unit 332 extracts tap from DST includingtrigger signaling information (PID of trigger stream) in operationS3060.

Then, the trigger signaling data receiving unit 332 extracts stream PIDfrom PMT including association_tag of the extracted Tap in operationS3070.

The trigger receiving unit 331 receives MPEG-2 TS packets correspondingto the extracted stream PID, and removes decapsulation, i.e., TS header,to restore PES stream including trigger stream. The stream_type of a PESpacket including trigger stream may be 0x06 representing synchronizeddata stream. The trigger receiving unit 331 parses at least one of PTSof a PES packet header from the restored PES stream, a target TDOidentifier in trigger stream, a trigger identifier, or trigger actioninformation in operation S3070.

Then, the service manager 350 performs an action on the target TDO atthe trigger timing by using the PTS of the PES packet header including atrigger as the trigger timing in operation S3080. Here, the target TDOmay be NRT service indicated by the parsed target TDO identifier.Additionally, the action may be one of preparation, execution,extension, and termination commands provided from the parsed triggeraction information.

FIG. 39 is a flowchart illustrating an operation of a receiver 300 whena trigger is transmitted using a trigger stream descriptor according toan embodiment.

When a physical transmission channel is selected in operation S3000 anda channel selected by a tuner is tuned, the receiver 300 obtains VCT andPMT from a broadcast signal received through the tuned physicaltransmission channel by using the demodulation unit 310 and thedemultiplexing unit 320 in operation S4000. The broadcast signalincludes VCT and PMT, and the trigger signaling data receiving unit 332or the PSI/PSIP section handler parses the obtained VCT and PMT.

Also, the trigger signaling data receiving unit 332 confirms whether atrigger is transmitted from the VCT and PMT to a corresponding virtualchannel. For this, the trigger signaling data receiving unit 332determines whether there is the Trigger_stream_descriptor in the ESdescriptor loop corresponding to a corresponding virtual channel inoperation S4020. Whether there is Trigger_stream_descriptor isdetermined by using whether a stream_type value is 0x06 (synchronizeddata streaming) and a descriptor_tag field of a corresponding descriptoris identical to a value set to correspond to a trigger stream descriptorafter searching descriptors in an ES descriptor loop.

If it is determined that Trigger_stream_descriptor is not identifiedfrom PMT and thus there is no Trigger_stream_descriptor, since acorresponding virtual channel does no transmit a trigger, the receiver300 operates properly according to broadcast service in thecorresponding virtual channel in operation S4025.

Then, if there is Trigger_stream_descriptor, the trigger signaling datareceiving unit 332 extracts Elementary_PID in the corresponding ES loopof PMT in operation S4030. The extracted stream PID may be a PID valueof stream including trigger stream.

Then, the trigger receiving unit 331 receives MPEG-2 TS packetscorresponding to the extracted stream PID, and performs decapsulation(i.e., removes a TS header) to restore PES stream including triggerstream. The stream_type of a PES packet including trigger stream may be0x06 representing synchronized data stream. The trigger receiving unit331 parses at least one of PTS of a PES packet header from the restoredPES stream, a target TDO identifier in trigger stream, a triggeridentifier, or trigger action information in operation S4040.

Then, the service manager 350 performs an action on the target TDO atthe trigger timing by using the PTS of the PES packet header including atrigger as the trigger timing in operation S4050. Here, the target TDOmay be NRT service indicated by the parsed target TDO identifier.Additionally, the action may be one of preparation, execution,extension, and termination commands provided from the parsed triggeraction information.

FIG. 40 is a flowchart illustrating an operation of a receiver when atrigger is transmitted using a stream type according to an embodiment.

When a physical transmission channel is selected and a channel selectedby a tuner is tuned, the receiver 300 obtains VCT and PMT from abroadcast signal received through the tuned physical transmissionchannel by using the demodulation unit 310 and the demultiplexing unit320. The broadcast signal includes VCT and PMT, and the triggersignaling data receiving unit 332 or the PSI/PSIP section handler parsesthe obtained VCT and PMT in operation S400.

Also, the trigger signaling data receiving unit 332 confirms whether atrigger is transmitted from the VCT and PMT to a corresponding virtualchannel. For this, the trigger signaling data receiving unit 332determines whether there is 0x96, i.e., the specific stream type in theES descriptor loop corresponding to a corresponding virtual channel inoperation S410.

If it is determined that 0x96 is not identified from stream type andthus there is no stream type, since a corresponding virtual channel doesno transmit a trigger, the receiver 300 operates properly according tobroadcast service in the corresponding virtual channel in operationS415.

Then, if the stream type is 0x96, the trigger signaling data receivingunit 332 extracts Elementary_PID in the corresponding ES loop of PMT inoperation S420. The extracted stream PID may be a PID value of streamincluding trigger stream.

Then, the trigger receiving unit 331 receives MPEG-2 TS packetscorresponding to the extracted stream PID, and performs decapsulation(i.e., removes a TS header) to restore PES stream including triggerstream. The trigger receiving unit 331 parses at least one of PTS of aPES packet header from the restored PES stream, a target TDO identifierin trigger stream, a trigger identifier, or trigger action informationin operation S430.

Then, the service manager 350 performs an action on the target TDO atthe trigger timing by using the PTS of the PES packet header including atrigger as the trigger timing in operation S440. Here, the target TDOmay be NRT service indicated by the parsed target TDO identifier.Additionally, the action may be one of preparation, execution,extension, and termination commands provided from the parsed triggeraction information.

FIG. 41 is a flowchart illustrating an operation of a receiver when atrigger is transmitted using AIT according to an embodiment.

The trigger signaling data receiving unit 332 receives AIT by using thedemodulation unit 310 and the demultiplexing unit 320 in operation S500.

Also, the trigger signaling data receiving unit 332 confirms whether atrigger is transmitted from AIT. For this, the trigger signaling datareceiving unit 332 confirms whether there is a trigger descriptor in AITin operation S510.

If it is determined that there is no trigger descriptor, since acorresponding application does not include a trigger, the receiver 300operates properly according to corresponding application service inoperation S515.

Also, if there is a trigger descriptor, the trigger receiving unit 332extracts trigger data from the trigger descriptor and parses theextracted trigger data to transmit it to the service manager 350 inoperation S530.

Then, the service manager 350 performs an action on the target TDO atthe trigger timing by using the parsed trigger data in operation S540.Here, the target TDO may be NRT service indicated by the parsed targetTDO identifier. Additionally, the action may be one of preparation,execution, extension, and termination commands provided from the parsedtrigger action information.

FIG. 42 is a flowchart illustrating an operation of a receiver when atrigger is transmitted using STT according to an embodiment.

The trigger signaling data receiving unit 332 receives STT by using thedemodulation unit 310 and the demultiplexing unit 320 in operation S600.

Also, the trigger signaling data receiving unit 332 confirms whether atrigger is transmitted from STT. For this, the trigger signaling datareceiving unit 332 confirms whether there is a trigger descriptor in STTin operation S610.

If it is determined that there is no trigger descriptor, since acorresponding STT does not include a trigger, the receiver 300 operatesproperly according to a broadcast signal in operation S615.

Also, if there is a trigger descriptor, the trigger receiving unit 332extracts trigger data from the trigger descriptor and parses theextracted trigger data to transmit it to the service manager 350 inoperation S630.

Then, the service manager 350 performs an action on the target TDO atthe trigger timing by using the parsed trigger data in operation S540.Here, the target TDO may be NRT service indicated by the parsed targetTDO identifier. Additionally, the action may be one of preparation,execution, extension, and termination commands provided from the parsedtrigger action information.

FIG. 43 is a timing diagram according to an embodiment of the presentinvention.

As shown in FIG. 43, since the transmitter 200 does not know when thereceiver 300 changes a channel, when the receiver 300 is power on, andwhen the receiver 300 selects a channel where a corresponding NRTservice exists, the transmitter 200 may transmit download contentstransmitted in an NRT way through terrestrial broadcasting periodicallyand repeatedly.

Referring to FIG. 43, an activation time T1 indicates a time at whichthe activation of an NRT(T1) service is triggered. An effective time Teindicates a time at which the NRT(T1) starts to be transmitted lastlybefore an activation time T1. A transmission period change time Toindicates a time at which a period of transmitting activation triggeringdata is changed. The transmission period change time To is a timeparameter that the transmitter 200 determines. A time window Tp1indicates a time prior to the effective time Te. A time window Tp2indicates a time between the effective time Te and the activation timeT1. A time window Tp3 indicates a time between the effective time Te andthe transmission period change time To. A time window Tp4 indicates atime between the transmission period change time To and the activationtime T1.

FIG. 44 is a flowchart illustrating an activation triggering datatransmitting method according to an embodiment of the present invention.

First, the trigger transmission unit 220 sets an activation time T1 ofan NRT(T1) service, i.e., a target object, in operation S5101, sets atransmission period change time To in operation S5103, and sets a shortperiod transmission count M in operation S5105.

When a current system time t is prior to the transmission period changetime To in operation S5107, the trigger transmission unit 220 transmitsactivation triggering data for the NRT(T1) service in a long period inoperation S5109. At this point, the trigger transmission unit 220 maytransmit activation triggering data in a period of n*Tp4.

Hereinafter, referring FIGS. 45 to 47, a triggering data transmissionpattern is described according to another embodiment of the presentinvention. Especially, a transmission pattern of maintenance triggeringdata (MTD) is described.

According to an embodiment, triggering data including a trigger actionset to a value corresponding to maintenance may be maintenancetriggering data.

FIG. 45 is a timing diagram according to another embodiment of thepresent invention.

In FIG. 45, an activation time Ta indicates an activation time of a TDOand a termination time Tf indicates a termination time of a TDO. Anadditional action time Taction indicates a time at which anotheradditional action for TDO is triggered (activated) after the activationtime Ta and before the termination time Tf. A time window Tplifeindicates a time between the activation time Ta and the termination timeTf, especially, the lifetime of a TDO. A time window Tp1 indicates atime between the activation time Ta and the additional action timeTaction. A time window Tp2 indicates a time between the additionalaction time Taction and the termination time Tf.

Moreover, FIG. 45 illustrates a case of when a TDO action occurs onetime at a Taction time in the time window Tplife.

FIG. 46 is a flowchart illustrating a maintenance triggering datatransmitting method according to an embodiment of the present invention.

A trigger transmission unit 220 sets an activation time Ta for TDO,i.e., a target object, in operation S5201.

The trigger transmission unit 220 determines a transmission period Pmtdof MTD for a target object in operation S5203. The transmission periodPmtd of MTD may be set to a predetermined value. Additionally, thetransmission period Pmtd of MTD may be set in consideration of a channelchange time of the receiver 300 or a time for power on/off of thereceiver 300.

When the current system time t is prior to the activation time Ta of atarget object in operation S5205, the trigger transmission unit 220 doesnot transmit MTD for the target object in operation S5207.

Moreover, when the current system time t is subsequent to the activationtime Ta of the target object in operation S5205 and is prior to thetermination time Tf of the target object in operation S5209, the triggertransmission unit 220 confirms a change of triggering data in operationS5211.

If the triggering data is changed, the trigger transmission unit 220transmits the changed triggering data and maintenance triggering dataincluding an additional action in operation S5213.

If the triggering data is not changed, the trigger transmission unit 220transmits the triggering data prior to the change and maintenancetriggering data including an additional action in operation S5215.

Moreover, when the current system time t is subsequent to thetermination time Tf of the target object in operation S5209, the triggertransmission unit 220 terminates the transmission of the maintenancetriggering data in operation S5217.

FIG. 47 is a view illustrating a maintenance trigger receiving methodaccording to an embodiment of the present invention.

First, the trigger receiving unit 331 of the receiver 300 receivesmaintenance triggering data in operation S5301. The reception ofmaintenance triggering data may be performed according to theabove-mentioned various embodiments.

If an object corresponding to a target service identifier of maintenancetriggering data is activated already in operation S5303, the servicemanager 350 of the receiver 300 maintains the activation of the objectin operation S5305.

If the object corresponding to a target service identifier ofmaintenance triggering data is not activated yet in operation S5303, theservice manager 350 of the receiver 300 activates the object inoperation S5307.

Hereinafter, referring FIGS. 48 to 50, a triggering data receptiontiming is described according to an embodiment of the present invention.Especially, a reception timing of preparation triggering data (PTD) isdescribed.

FIG. 48 is a timing diagram according to an embodiment of the presentinvention.

In FIG. 48, a preparation trigger time Tp indicates a time at which thepreparation of a TDO is triggered by PTD. An activation time Taindicates an activation time of a TDO and a termination time Tfindicates a termination time of a TDO.

A time window Tpa indicates a time between a preparation trigger time Tpand the activation time Ta and a time window Tplife indicates a timebetween the activation time Ta and the termination time Tf.

The time window Tpa may vary according to an advance task or acorresponding advance task.

FIG. 49 is a flowchart illustrating a preparation trigger receivingmethod according to an embodiment of the present invention.

Especially, FIG. 49 illustrates a method of processing downloadingpreparation triggering data.

FIG. 50 is a flowchart illustrating a preparation trigger receivingmethod according to another embodiment of the present invention.

Especially, FIG. 50 illustrates a processing method of PTD requiring thebackground activation of a TDO to prepare the TDO.

Thus, trigger may be classified as a preparation trigger, an activationtrigger, and a maintenance trigger according to its characteristic.

A method of identifying such three triggers and a cross-reference methodbetween three triggers will be described later.

FIG. 51 is a flowchart illustrating a bitstream syntax of a triggerconfigured according to another embodiment of the present invention.

The trigger according to the syntax shown in FIG. 51 further includes atrigger type field trigge_type and a reference target trigger identifierfield target_trigger_id_ref, compared to the trigger according to thesyntax shown in FIG. 25.

FIG. 53 is a view illustrating a syntax of an internet locationdescriptor according to an embodiment of the present invention.

As shown in FIG. 53, the internet location descriptor includes adescriptor tag field descriptor_tag, a descriptor length fielddescriptor_length, a URL count field URL_count, a URL length fieldURL_length, and a URL( ) field.

FIG. 54 is a flowchart illustrating a trigger transmitting methodaccording to an embodiment of the present invention.

The transmitter 200 transmits a preparation trigger in operation S6003at the transmission timing of the preparation trigger in operationS6001, transmits an activation trigger in operation S6007 at thetransmission timing in operation S6005, and transmits a maintenancetrigger S6011 at the transmission timing of the maintenance trigger inoperation S6009.

In relation to the transmission of a preparation trigger, an activationtrigger, and a maintenance trigger, according to an embodiment, apreparation trigger, an activation trigger, and a maintenance triggermay be included in one stream and transmitted.

Then, an operating method of a receiver 300 according to an embodimentof the present invention will be described with reference to FIGS. 55 to57.

FIG. 55 is a flowchart illustrating an operating method of a receiveraccording to an embodiment of the present invention.

The receiver 300 receives a trigger in operation S6101. Especially,receiver 300 may receive a trigger in the same manner as shown in FIGS.36 to 42.

The receiver 300 confirms a type of the received trigger in operationS6103. The receiver 300 may confirm a type of the received trigger in amanner described above. For example, the receiver 300 may confirm a typeof a trigger through at least one of a trigger type field trigge_typeand a trigger action field trigger_action in the trigger. Additionally,the receiver 300 may confirm a type of a trigger on the basis of whethera target TDO is activated or whether a trigger time elapses.

If the received trigger is a preparation trigger in operation S6105, thereceiver 300 processes the received preparation trigger in operationS6107. The processing of the preparation trigger by the receiver 300 wasdescribed in relation to a trigger action field of a preparationtrigger. A state of a TDO may be changed through such processing of apreparation trigger.

According to another embodiment, when a preparation trigger triggersdownloading of a content item, the receiver 300 may recognize thelocation information of a content item to be downloaded from an internetlocation descriptor in the preparation trigger, and may download thecontent item through the recognized location.

Again, FIG. 55 will be described.

If the received trigger is an activation trigger in operation S6109, thereceiver 300 processes the received activation trigger in operationS6111. The processing of the activation trigger by the receiver 300 wasdescribed in relation to a trigger action field of an activationtrigger. A state of a TDO may be changed through such processing of anactivation trigger.

If the received trigger is a maintenance trigger in operation S6113, thereceiver 300 processes the received maintenance trigger in operationS6115.

FIG. 57 is a TDO state transition diagram illustrating a method ofprocessing a trigger by a receiver according to an embodiment of thepresent invention.

As shown in FIG. 57, a target TDO is in one of a released state ST110such as a non-ready state, a ready state ST120, an active state ST130,and a suspended state ST140.

Hereinafter, according to an embodiment of the present invention, amethod of providing information on NRT service in linkage with an NRTservice, a real time broadcast, and an internet network will bedescribed.

As mentioned above, in an actual broadcast system, one broadcast programmay include at least one application executed in linkage with acorresponding program, and such an application may be stored in thereceiver 300 and executed through the above-mentioned NRT servicereceiving method.

However, since a PSIP table does not include information on an NRTservice linked with a broadcast program, when the receiver 300 is toreceive an NRT service linked with a broadcast program, an NRT-IT of achannel that a specific broadcast program belongs all needs to beparsed. Also, even when the receiver 300 receives the NRT-IT first toreceive a content item of NRT service, it is difficult to identify abroadcast program linked with the content item. Additionally, since thePISP table does not include information on an internet network, thereceiver 300 receives only a real time broadcast program, so that it isdifficult to recognize related service transmitted through an internetnetwork. Additionally, for the same reason as above, it is difficult forthe receiver 300 to receive extended EPG on a specific real timebroadcast program, which is transmitted through an internet network.Accordingly, a systematic linkage between a real time broadcast program,NRT service, and an internet network is required.

According to an embodiment of the present invention, the transmitter 200may include NRT service information such as an NRT or a TDO orinformation used for linking with an internet network in a PSIP tablecorresponding to a specific channel or program, and then may transmitthe PSIP table. Moreover, PSIP table information corresponding tospecific real time broadcast channel information or program informationmay be included in an NRT service, and then transmitted.

Accordingly, the receiver 300 may receive a real time broadcast channelor program, and parses the PSIP table, so that it may selectivelyreceive an NRT service linked with a specific broadcast program.Furthermore, the receiver 300 receives a real time broadcast channel orprogram, and parses the PSIP table, so that it may receive an NRTservice linked with a specific broadcast channel or program, through aninternet network. Then, the receiver 300 may receive NRT service toobtain PSIP table information on a broadcast program linkable with theNRT service and then, may provide it to a user.

According to an embodiment of the present invention, a descriptorproviding information linked with a real time broadcast, for example,one of NRT service, preview information, extended EPG information,highlight information, and related internet portal information, may beincluded in one of PSIP tables and then, transmitted. According to anembodiment of the present invention, such a descriptor may be referredto as a link descriptor.

Additionally, according to an embodiment of the present invention,information on a broadcast program linkable with NRT service, forexample, broadcast channel information or program information, may beincluded in one of an SMT and an NRT such as an NRT-IT and then,transmitted. According to an embodiment of the present invention, such adescriptor may be referred to as an event descriptor.

FIG. 58 is a view illustrating a syntax of a link descriptorlink_descriptor according to an embodiment of the present invention.FIGS. 59 and 60 are views illustrating contents of fields included in alink descriptor.

As shown in FIG. 58, the link descriptor includes a descriptor tag fielddescriptor_tag, a descriptor length field descriptor_length, a linkcount field number_of_links, and a plurality of link data items. Each ofthe plurality of link data items includes a link type field link_type, alink media field link_media, an MIME type length field mime_type_length,an MIME type field mime_type, a descriptor length fielddescription_length, a description field description, a link length fieldlink_length, and a link byte field link_byte.

The link number field number_of_links may be an 8-bit unsigned integerto indicate the number of a plurality of link data items.

The link type field link_type indicates a type of a receivable relatedservice on the basis of a link byte field in a link data item. Forexample, as shown in FIG. 44, the link type field may indicate typeinformation of receivable specific service on the basis of a link bytefield included in a link data item.

The link media field link_media may be an 8-bit unsigned integerindicating a transmission medium to receive related service on the basisof a link data item. For example, as shown in FIG. 60, when the linkmedia field is 0x02, it indicates that related service receivable basedon a link data item is receivable through NRT service. Additionally,when the link media field is 0x03, it indicates that related service isreceivable through internet service.

The link byte field link_byte may be a field indicating data to receivethe above-mentioned broadcast program related service. The link bytefield may include identification information of contents receivablethrough a link medium. For example, as shown in FIG. 60, if the linkmedium is NRT service, the link byte field may include a serviceidentifier and a content identifier service_id and content_linkage toreceive NRT service. Additionally, if the link medium is internetservice, the link byte field may include a uniform resource identifier(URL), i.e., internet address information, or URL information.

FIGS. 61 and 62 are views illustrating a linkage between each table whenthe link descriptor of FIG. 43 is included in a descriptor of an eventinformation table (EIT) among PSIP tables according to an embodiment ofthe present invention.

As shown in FIG. 61, the link descriptor may be included in a descriptorloop of an EIT indicating broadcast program information and then,transmitted.

The EIT in addition to a VCT is included in a PSIP and then,transmitted. Since the VCT includes source_id corresponding to selectedvirtual channel number channel_number, the receiver 300 parses an EITincluding the same source_id as the VCT to obtain information on eachbroadcast program provided from a corresponding virtual channel. Eachbroadcast program is identified by event_id

Accordingly, the receiver 300 may extract a link descriptor from a loopincluding event_id of a specific broadcast program in an event loop inthe parsed EIT, and may receive information linked to the specificbroadcast program by using the extracted link descriptor through NRTservice or an internet network.

For example, as shown in FIG. 61, if the link descriptor may include aservice identifier service_id and a content identifier content_linkageof an NRT service linked to the specific broadcast program. In thiscase, the receiver 300 may recognize content item location informationof the linked NRT service through an SMT, an NRT-IT, and an FDT, anddownloads a content item through the recognized location information.

In more detail, the receiver 300 may obtain service signaling channelinformation corresponding to a service identifier included in a linkbyte field of a link descriptor, from an SMT. At this point, the servicesignaling channel information may include an IP address and a portnumber. Moreover, the receiver 300 may obtain a list of contentindenters content linkage in a service corresponding to a serviceidentifier included in a link byte field of a link descriptor, from anNRT_IT. The receiver 300 may recognize the identifier of a content itemto be downloaded, which corresponds to a service identifier in anNRT_IT, through a content linkage field in a link byte field of a linkdescriptor. Then, the receiver 300 may recognize the locations ofcontent item files corresponding to a content identifier in an NRT_ITfrom a FLUTE FDT received through the IP address and port number of anSMT. Accordingly, the receiver 300 may receive files configuring acontent item of NRT service linked with a corresponding broadcastprogram by using a FLUTE FDT through a FLUTE session. Moreover, thereceiver 300 may extract URL information of content items, for example,a URL list of files, linked with a broadcast program from an internetlocation descriptor described later in an NRT_IT, and based on theextracted list, may receive files configuring a content item of NRTservice linked with a broadcast program through a network.

Furthermore, a link descriptor may include at least one of portal HTMLpage access information relating to a broadcast, Thumbnail receptioninformation, Preview Clip reception information, Extended EPG receptioninformation, highlight reception information, Multiview receptioninformation, and linkable TDO reception information, in addition to NRTservice linked to a broadcast program. A link descriptor may includeinformation to receive such reception information through NRT service oran internet network.

In more detail, the receiver 300 may obtain an EIT corresponding to aselected virtual channel, obtain a link descriptor from a descriptorloop of an event loop (i.e., a for loop including event_id)corresponding to a selected broadcast program in the obtained EIT,extract an internet address from the obtained link descriptor, andreceive a service linked to a selected broadcast program in access to aninternet network according to the extracted internet address.Accordingly, a broadcast service provider may provide a service linkedwith a specific broadcast program through a real time broadcast.Moreover, the receiver 300 may access an internet network by usinginternet address information, and may receive a service linked with acorresponding broadcast program through an internet network.

FIG. 63 is a view illustrating a syntax of an event descriptor(Event_descriptor) and contents of fields in the event descriptoraccording to an embodiment of the present invention.

As shown in FIG. 63, the event descriptor includes a descriptor_tagfield, a descriptor_length field, and an ETM_id field.

FIG. 64 is a view illustrating a method of identifying a linkage programthrough the event descriptor according to an embodiment of the presentinvention.

For example, as shown in FIG. 64, the service manager 350 of thereceiver 300 identifies service_id through an SMT and receives andparses a content item of an NRT service corresponding to service_ididentified by an NRT-IT.

Then, the service manager 350 of the receiver 300 may identify a virtualchannel matching source_id from a VCT, and may identify an event loop ofa broadcast program matching event_id from an EIT of a correspondingvirtual channel. The service manager 350 of the receiver 300 receivesNRT server related broadcast program information from the identifiedevent loop and then, provides the information to a user. The broadcastprogram information may include at least one of a start time of acorresponding broadcast program, an ETT position, a broadcasting time,title information, and description information in the event loop of anEIT. Accordingly, the service manager 350 of the receiver 300 providesto a user the information on the received NRT service related broadcastprogram on the basis of the received broadcast program information.

FIG. 65 is a flowchart illustrating an operation of receiving by thereceiver 300 broadcast program or broadcast channel related contents byusing the link descriptor according to an embodiment of the presentinvention.

Referring to FIG. 65, when the receiver 300 is turned on, it receives aVCT or an EIT by receiving a PSIP table through a PSIP/PSI handler orservice manager in operation S7000. The PSIP/PSI handler or servicemanager 350 of the receiver 300 parses each table of the PSIP table andobtains VCT or EIT from the parsed tables.

Also, the service manager 350 of the receiver 300 searches for adescriptor loop from the received VCT or EIT in operation S7010. Then,the service manager 350 of the receiver 300 determines whether there isa link descriptor through searching in operation S7020.

Also, when it is determined that there is a link descriptor, the servicemanager 350 of the receiver 300 extracts link information from the linkdescriptor, and based on the extracted link information, displays abroadcast program including the link descriptor or a broadcast channelrelated content list in operation S7030.

Then, the service manager 350 of the receiver 300 determines whethercontent is selected and there is a receive instruction in operationS7040. The content may be selected by a user or a predetermined process.The selected content may be content displayed on the above-mentioneddisplayed broadcast channel or broadcast program related content list.Moreover, a user may input a receive instruction on the selectedcontent, and also a receive instruction on the selected content may beperformed by a predetermined process.

Then, when a receive instruction on the selected content is executed,the service manager 350 of the receiver 300 receives correspondingcontent immediately or perform reception reservation in operation S7050.

Then, when contents reserved for reception is NRT service, the servicemanager 350 of the receiver 300 receives an SMT to identifycorresponding NRT service in operation S7060. Then, the service manager350 of the receiver 300 accesses a FLUTE session through theabove-mentioned method in operation S7070 and identifies a packet forthe content reserved for reception among packets of a content item fileconfiguring NRT service in operation S7080. Then, the service manager350 of the receiver 300 receives the identified packets for the contentreserved for reception through FLUTE or an internet network in operationS7090.

FIG. 66 is a flowchart illustrating an operation of providing by thereceiver 300 broadcast program related content by using an eventdescriptor according to an embodiment of the present invention.

According to an embodiment of the present invention, as shown in FIG.66, the transmitter 200 inserts broadcast program information linkedwith NRT service into the event descriptor and inserts the eventdescriptor into a content loop of NRT-IT to be transmitted to thereceiver 300 through a broadcast channel or NRT service signalingchannel.

When NRT-IT including the event descriptor is transmitted in such a way,a PSIP/PSI handler or service manager 350 of the receiver 300 parses aPSIP table to obtain a VCT and an EIT in operation S7100. The receiver300 may provide information on a broadcast channel and broadcast programselected through a VCT and an EIT to a user.

Also, the service manager 350 of the receiver 300 determines whether NRTservice is transmitted through an NRT service signaling channel or aninternet network, and receives an SMT and an NRT-IT when NRT service istransmitted in operation S7120.

Then, the service manager 350 of the receiver 300 searches for a contentloop of an NRT-IT and parses descriptor_tag of each descriptor toidentify descriptors in the content loop in operation S7120. Then, theservice manager 350 of the receiver 300 determines whether there is anevent descriptor in the parsed descriptor in operation S7130.

If there is an event descriptor, the service manager 350 of the receiver300 displays broadcast channel information or broadcast programinformation in the event descriptor (for example, a broadcast channelnumber based on source_id or broadcast program EPG information based onevent_id) in operation S7140, and represents that the information islinked with receivable NRT service.

Then, the service manager 350 of the receiver 300 determines whether thecontent of NRT service linked with a broadcast program is selected andthere is a receive instruction in operation S7150.

Then, when a receive instruction on the selected content is executed,the service manager 350 of the receiver 300 receives correspondingcontent immediately or perform reception reservation in operation S7160.According to an embodiment of the present invention, the selectedcontent may be NRT service. Accordingly, the service manager 350 of thereceiver 300 accesses a FLUTE session or internet network on the basisof the pre-received SMT and NRT-IT to receive the selected content suchas NRT service in operation S7170.

Then, as shown in FIG. 65, the service manager 350 of the receiver 300identifies a packet for content reserved for reception among packets ofa content item file configuring NRT service in operation S7180. Then,the service manager 350 of the receiver 300 receives the identifiedpackets for the content reserved for reception through FLUTE or aninternet network in operation S7190.

FIG. 67 is a view illustrating a syntax of NRT_service_descriptor, thatis, a service level descriptor.

As shown in FIG. 67, NRT_service_descriptor in service level descriptorsmay include information on NRT service transmitted. The information onNRT service may include auto update, the length of content, savereservation information, or consumption_model information.

Especially, a consumption_model field in a box may include informationon a service providing method of NRT service transmitted. Accordingly,the service manager 350 of the receiver 300 determines a properprocessing method according to each NRT service on the basis of theconsumption_model field, and provides NRT service according to thedetermined method.

According to an embodiment of the present invention, the transmitter 200presets an NRT service providing method applicable to an TDO andallocates a specific value to the consumption_model field to correspondto the TDO. Accordingly, the transmitter 200 may allocate a valuecorresponding to a TDO to the consumption_model field and then transmitit.

Then, the service manager 350 of the receiver 300 receives theconsumption_model field and determines that an TDO is transmitted andthen, receives the TDO according to a predetermined service providingmethod to provide it.

FIG. 68 is a view illustrating a meaning according to each value of aconsumption_model field in NRT_service_descriptor according to anembodiment of the present invention.

The consumption_model field is included in NRT_service_descriptor and isa field indicating which method for consumption_model NRT service thatNRT_service_descriptor indicates uses. NRT service may be providedaccording to a consumption model of one of Browse&Download service,portal service, and push. Additionally, NRT service may be provideddepending on a TDO consumption model according to an embodiment of thepresent invention.

In more detail, when the consumption_model field is a TDO consumptionmodel, the service manager 350 of the receiver 300 receives acorresponding NRT service (TDO), and by using at least one of the linkdescriptor or event descriptor, obtains NRT service related real-timebroadcast channel or program information. Additionally, the servicemanager 350 of the receiver 300 may receive a trigger included inreal-time broadcast to operate a TDO at a specific time or may downloada content item in advance.

Moreover, in the case of a TDO consumption model, when each content itemis displayed in a currently selected NRT service, it may be downloadedimmediately. When an update version of each content item is displayed ina currently selected NRT service, it may be updated immediately. Also,each content item may be executed or terminated by a trigger.

FIG. 69 is a flowchart illustrating an operation of the receiver 300when a TDO is transmitted by a TDO consumption model according to anembodiment of the present invention.

First, the receiver 300 receives an SMT in operation S8000, and parses aservice level descriptor in operation S8010. The receiver 300 mayreceive an SMT through a service signaling channel by using the servicemanager 350, and may parse service level descriptors including an NRTdescriptor in a service level descriptor loop in each NRT service loop.

Then, the receiver 300 confirms NRT_service_descriptor in the parsedeach service level descriptor, and determines whether a value of theconsumption_model field in NRT_service_descriptor is 0x04, i.e., a TDOconsumption model, in operation S8030. If the value is not 0x04, thereceiver 300 operates according to another NRT service consumptionmodel.

However, if the value is 0x04, the receiver 300 determines that an NRTservice designated as a TDO consumption model is transmitted. In thiscase, the receiver 300 determines whether a TDO automatic reception isset in operation S8040. If the automatic reception is not set, thereceiver 300 displays TDO service and a list of contents in the TDOservice, and displays a TDO reception selection screen in operationS8045. Then, the receiver 300 receives a TDO service selected by a userin operation S8047.

Moreover, when the automatic reception is set, the receiver 300 receivesa TDO without a user's selection in operation S8050.

Then, the receiver 300 determines whether a trigger is received afterreceiving the TDO in operation S8060.

Additionally, the receiver 300 receives and manages an NRT service thata user selects through the service manager 350. However, in the case ofTDO service, since it operates in linkage with real-time broadcast andis triggered by a trigger, storing and managing the TDO service may beaccomplished according to the intentions of real-time broadcast serviceproviders.

Therefore, according to an embodiment of the present invention, in thecase of a TDO consumption model type in which TDO service istransmitted, the receiver 300 allocates a predetermined area of astorage unit as a TDO storage area, and then, receives TDO service,stores the received TDO service in the allocated area, and manages it.Furthermore, the TDO storage area is designated by the transmitter 200,and then, the TDO service is transmitted to the receiver 300. In thiscase, the receiver 300 may receive, store, and manage the TDO service inthe allocated area.

FIG. 70 is a flowchart illustrating a method of allocating and managingby the receiver 300 a TDO storage area according to a TDO consumptionmodel.

Referring to FIG. 70, first, the receiver 300 determines a consumptionmodel of NRT service transmitted after operations S8000 to S8020 of FIG.69 are performed. Then, the receiver 300 determines whether an NRTservice of a TDO consumption model type, for example, TDO service, istransmitted based on a consumption model field in operation S8110.

When the consumption model field indicates a TDO consumption model, thereceiver 300 extracts a storage_reservation field ofNRT_service_descriptor in operation S8310. The storage_reservation fieldmay be a value corresponding to a storage space essential for acorresponding TDO service. The transmitter 200 may designate a spacevalue for TDO storage area in the storage_reservation field andtransmits it.

Then, the receiver 300 allocates a storage area for TDO servicereception and operation on the basis on the storage_reservation fieldvalue in operation S8140.

Then, the receiver 300 receives TDO service in an area allocated as aTDO service storage area in operation 8150 and stores and manages thereceived TDO service.

In such a way, the receiver 300 allocates a storage area for TDO serviceand manages it on the basis of the consumption model field and storagereservation field of NRT service. However, the above method is just oneembodiment and is not limited to a storage method according to eachvalue of a consumption model field and a storage reservation field.

Moreover, a TDO may mean an NRT service providing a TDO, or each ofcontent items configuring TDO service. Moreover, each content item issignaled through an NRT-IT, and the receiver 300 receives data signaledthrough the NRT-IT and recognizes information on a TDO. However, NRT-ITdoes not include information for TDO, for example, a trigger time, anexecution termination time, an execution priority, and an additionaldata receiving path, besides information provided for general NRTservice. Accordingly, it is difficult for the receiver 300 to understandthe attribute of a TDO in detail and operates smoothly. Especially, whenthe receiver 300 manages a storage space, TDO services of a plurality ofTDOs provided, or additional data of TDO service, information on TDO isinsufficient.

Therefore, according to an embodiment of the present invention, a methodof including specific property information of a TDO in TDO metadata andan operation of the receiver 300 according thereto are suggested.

FIG. 71 is a view illustrating a TDO metadata descriptor according to anembodiment of the present invention.

Referring to FIG. 71, TDO metadata includes a descriptor_tag field, adescriptor_length field, a scheduled_activation_start_time field, ascheduled_activation_end_time field, a priority field, anactivation_repeat_flag field, and a repeat_interval field.

The scheduled_activation_start_time field and thescheduled_activation_start_time field may be used to allow the receiver300 to synchronize a TDO with real-time broadcast and operate it.Additionally, the receiver 300 may selectively download a TDO on thebasis of the scheduled_activation_start_time field and thescheduled_activation_start_time field and may determine the downloadorder of TDOs. Additionally, the receiver 300 may determine the deletionorder of TDOs on the basis of the scheduled_activation_start_time fieldand the scheduled_activation_start_time field. Especially, the receiver300 identifies a TDO having a scheduled_activation_start_time fieldvalue closest to the current time (i.e., a TDO to be activated first),and downloads and stores the identified TDO first. Additionally, thereceiver 300 may delete a TDO having a scheduled_activation_start_timefield value that is the latest from the current time if a storage spaceis insufficient.

The receiver 300 may sequentially receive or store a plurality of TDOson the basis of a priority field allocated to each TDO. Moreover, thereceiver 300 may execute at least one of a plurality of TDOs on thebasis of a priority field allocated to each TDO.

Moreover, the receiver 300 may automatically execute a TDO on the basisof such a priority field. For example, if there are a plurality of TDOsto be executed within a specific time range, the receiver 300 selects aTDO having a high or low priority field and automatically executes it onthe basis of a priority field corresponding to each TDO.

The repeat_interval field may mean the execution period of a TDOaccording to each value as shown in Table 4.

TABLE 4 2 Every week 4-6 times 3 Every week 2-3 times 4 Every week 5Biweekly 6 Every month 7 Once in two months 8 Once a quarter 9 Once insix months 10  Every year 11-255 Reserved

In such a way, the transmitter 200 may transmit a TDO metadatadescriptor through an NRT service signaling channel or an internetnetwork. Additionally, the transmitter 200 inserts a TDO metadatadescriptor into a content_level_descriptor loop of NRT-IT to transmitadditional information on a corresponding TDO.

Moreover, the receiver 300 may receive TDO metadata through an NRTservice signaling channel or an internet network to obtain informationon a TDO.

FIG. 72 is a flowchart illustrating an operation of receiving by thereceiver 300 TDO metadata according to an embodiment of the presentinvention.

Referring to FIG. 72, the receiver 300 receives an SMT and an NRT-ITtransmitted through a service signaling channel in operation S8200.

According to an embodiment, the transmitter 200 includes a TDO metadatadescriptor in a content level descriptor loop and then, transmits it.Accordingly, the receiver 300 searches for the content level descriptorloop of the received NRT-IT in operation S8220.

Then, if there is a TDO metadata descriptor, the receiver 300 extractsTDO metadata from a TDO metadata descriptor in operation S8230.

Then, the receiver 300 obtains necessary information from the extractedTDO metadata and manages a TDO on the basis of the obtained informationin operation S8240.

FIG. 73 is a flowchart illustrating a method of the receiver 300 tomanage a TDO depending on time information in TDO metadata according toan embodiment of the present invention.

Referring to FIG. 73, the receiver 300 determines whether a storagespace for TDO is insufficient in a storage unit in operation S8300.

Then, if it is determined that a storage space is insufficient, thereceiver 300 extracts time information from the TDO metadata on each TDOin operation S8310.

Then, the receiver 300 first deletes a TDO having the largest value of ascheduled activation start time field on the basis of a scheduledactivation start time for each TDO in operation S8320.

Then, the receiver 300 first receives a TDO having the smallest value ofa scheduled activation start time field on the basis of a scheduledactivation start time for each TDO in operation S8330.

In addition, time information in TDO metadata may include a time slotdescriptor for providing activation time information of a TDO inaddition to scheduled activation start and end time fields. The timeslot descriptor may include a slot start time, a slot length, and repeatinformation, by using a time at which a TDO is performed as one slot.Accordingly, the receiver 300 extracts a time slot at which a TDO isactivated, so as to predict a repeated execution and end time of theTDO.

FIG. 74 is a flowchart illustrating a method of the receiver 300 tomanage a TDO depending on time information and priority information inTDO metadata according to another embodiment of the present invention.

Referring to FIG. 74, first, the receiver 300 receives TDO metadata, anddetermines whether there are a plurality of TDOs executable at aspecific time in operation S8400.

Also, when it is determined that there are a plurality of TDOs, thereceiver 300 extracts a priority value for each TDO from the TDOmetadata in operation S8410.

Then, the receiver 300 provides a list of a plurality of TDO executableat a specific time to a user on the basis of the extracted priority inoperation S8420.

Then, when a TDO is selected by a user, the receiver 300 receives theselected TDO, and performs a trigger action on the selected TDO at aspecific time, for example, a trigger time.

According to an embodiment of the present invention, the transmitter 200may designate the URL of content item files transmitted through abroadcast network and an IP network by using an internet locationdescriptor. This internet location descriptor may be included in acontent level descriptor loop of an NRT-IT. Accordingly, the transmitter200 includes URL information on internet where each file placed in aninternet location descriptor and transmits it.

One example of such an internet location descriptor is described withreference to FIG. 75.

FIG. 75 is a view illustrating a syntax of an internet locationdescriptor according to another embodiment of the present invention.

When the URLs of files configuring a content item are transmitted byusing an internet location descriptor shown in FIG. 75, a URLcorresponding to each file is designated and needs to be included in aninternet location descriptor. However, when the number of files isincreased, the number of URLs to be designated is increased, so thattransmission efficiency may be reduced. Moreover, the number of URLs isincreased, their management becomes complex and difficult.

Accordingly, the transmitter 200 according to an embodiment of thepresent invention includes list information of URLs corresponding toeach file in a FLUTE file description table (FDT), and transmits the FDTthrough an internet network instead of a FLUTE session. The transmitter200 may transmit list information of URLs or an FDT by using theinternet location descriptor, and also may transmit list information ofURLs or an FDT by using the link descriptor.

The receiver 300 receives URL information of the FDT located through alink descriptor or an internet location descriptor, and receives the FDTon the basis of the received URL information through an internetnetwork. Then, the receiver 300 receives files configuring a contentitem on the basis of URL information of each file in the FDT. In such away, by transmitting the URL of FDT, it is not necessary to designate aURL to each of a plurality of files. As a result, transmissionefficiency may be increased.

FIG. 76 is a flowchart illustrating an operation of the receiver 300when FDT is transmitted through an internet network according to anembodiment of the present invention.

Referring to FIG. 76, the receiver 300 first receives an SMT and anNRT-IT through the service manager 350 in operation S8500.

Then, the service manager 350 of the receiver 300 selects NRT service ora content item to be received in operation S8510. The service manager350 of the receiver 300 selects NRT service to be received according toa predetermined condition. Additionally, the service manager 350 of thereceiver 300 selects NRT service to be received according to a user'sinput.

Then, the service manager 350 of the receiver 300 determines whether toreceive each file configuring a content item of the selected NRT servicethrough internet in operation S8520. The service manager 350 of thereceiver 300 determines whether to receive each file through internet onthe basis of a connection state of the internet network. Additionally,the service manager 350 of the receiver 300 determines whether toreceive each file through internet according to a user's setting.

Then, when it is determined that each file is not received throughinternet, the service manager 350 of the receiver 300 accesses a FLUTEsession through an NRT service signaling channel, and receives each fileconfiguring a content item of the selected NRT service in operationS8525. An operation of receiving NRT service through a FLUTE session isdescribed above.

However, when it is determined that each file is received throughinternet, the service manager 350 of the receiver 300 receives FDTthrough internet in operation S8530. The service manager of the receiver300 receives URL information of FDT through a link descriptor or aninternet location descriptor, and receives the FDT located on aninternet network on the basis of the received URL information of theFDT.

Here, the FDT may include a list index of each file configuring acontent item in a FLUTE session. A MIME type designation is necessary inorder to additionally transmit the FDT through an internet network. TheMIME type means a specific format to indicate the type of a contenttransmitted through an internet network. Various file formats areregistered as MIME types and are used in internet protocols such as HTTPand SIP. The MIME type registration is managed by IANA. MIME may definea message format of a tree structure. According to an embodiment of thepresent invention, an MIME type corresponding to FDT may be defined as aformat such as application/nrt-flute-fdt+xml. Additionally, the receiver300 parses a URL having the MIME type and, based on this, receives FDT.

When receiving an FDT, the service manager 350 of the receiver 300obtains URL information of files configuring each content item from theFDT in operation S8540. Then, the service manager 350 of the receiver300 receives each file on the basis of the obtained URL informationthrough internet in operation S8550. The service manager 350 of thereceiver 300 connects the received files on the basis of a contentlinkage field of the FDT, so that it obtains a content item.

Then, the service manager 350 of the receiver 300 provides NRT servicethrough the received content item in operation S8560.

As mentioned above, since the receiver 300 receives the FDT throughinternet, it is not necessary to receive URL information of each fileand it is possible to efficiently receive NRT service through aninternet network. Moreover, according to an embodiment of the presentinvention, an arbitrary file including a file list (index) may betransmitted instead of FDT.

FIG. 77 is a flowchart illustrating an operation of the receiver 300when the URL of an FDT is transmitted through a link descriptoraccording to an embodiment of the present invention.

According to an embodiment of the present invention, the transmitter 200includes the link descriptor in one of EIT, VCT, or PMT and transmitsit, and the link descriptor includes URL information for obtaining FDT.

First, when the receiver 300 is turned on, a broadcast channel or abroadcast program is selected in operation S8600.

Then, the receiver 300 receives at least one of an EIT, a VCT, or a PMTthrough the service manager 350 or a PSIP/PSI handler in operationS8610, extracts a link descriptor in operation S8620, and obtains theURL information of an FDT from the link descriptor in operation S8630.

Then, the service manager 350 of the receiver 300 receives an FDT fileby using the obtained URL information of the FDT through internet inoperation S8640.

Then, the service manager 350 of the receiver 300 obtains URLinformation of each file included in the FDT in operation S8650. The URLinformation of each file included in the FDT may include positioninformation on internet of files configuring a content item of NRTservice.

Then, the service manager 350 of the receiver 300 receives designatedfiles according to the obtained URL information through internet inoperation S8660 and stores the received files as a content item inoperation S8670.

Through such a process, the receiver 300 may receive FDT including afile list configuring a content item of NRT service through an internetnetwork. Moreover, since each file is received based on an FDT throughinternet, efficient transmission is possible.

FIG. 78 is a flowchart illustrating an operation of the receiver 300when the URL of FDT is transmitted through NRT-IT according to anembodiment of the present invention.

According to an embodiment of the present invention, the transmitter 200includes the internet location descriptor in a content descriptor loopof an NRT-IT and transmits it, and the internet location descriptorincludes URL information for obtaining FDT.

First, the receiver 300 receives the NRT-IT through the service manager350 in operation S8700.

Then, the receiver 300 extracts an internet location descriptor from acontent descriptor loop content_descriptor( ) of the NRT-IT through theservice manager 350 in operation S8610, obtains URL information of anFDT from the internet location descriptor in operation S8630, receivesthe FDT by using the URL information of the FDT through an internetnetwork in operation S8740, and obtains URL information of a fileconfiguring each content item from the FDT in operation S8750.

Here, the receiver 300 receives URL information of FDT through aninternet location descriptor, and also receives FDT in access to a FLUTEsession through an SMT and an NRT-IT. Additionally, the URL of each filein an FDT may indicate the address of an internet network, and may alsoindicate a file position in a FLUTE session. Accordingly, the receiver300 determines the URL format of each file from the FDT, and selectivelyreceives each file through one of a FLUTE session and an internetnetwork according to the determined format.

Additionally, the receiver 300 receives an FDT through an internetnetwork, and receives files configuring a content item in access to aFLUTE session on the basis of the received FDT.

Moreover, the transmitter 200 designates a transmission preferred pathwhen each file is transmittable through both a FLUTE session and aninternet network. The transmission priority path may be designated as anattribute of File type: complex type by using xml schema. For example,it may be designated as <xs:attribute name=“Internet_preferred”type=“s:boolean” use=“optional” default=“false”/>. Here,internet_preferred means preferred transmission through an internetnetwork, and when a type value is true, it means that preferredtransmission through an internet network is performed. Additionallydefault is defined as false and this indicates that preferredtransmission through a FLUTE session is performed by default.Accordingly, the receiver 300 confirms the attribute of each file typeto selectively receive each file through one of a FLUTE session and aninternet network.

Then, the service manager 350 of the receiver 300 receives designatedfiles according to the obtained URL information of the files through aFLUTE session or an internet network in operation S8760 and stores thereceived files as a content item in operation S8670.

Additionally, a service provider determines a consumption modelcorresponding to NRT service and then, allocates a consumption modelfield value corresponding thereto to NRT service and transmits it. Inthe case of the above consumption models, the receiver 300 provides NRTservice on the basis of one content item. However, with one contentitem, it is difficult to generate a user interface linked with real-timebroadcast or provide a complex and diverse NRT service.

Accordingly, according to an embodiment of the present invention, an NRTservice provider may provide a plurality of content items through thetransmitter 300 but an NRT service provider may set one content item tocontrol an operation of another content item. The receiver 300 receivesthis, and identifies a consumption model providing a plurality ofcontent items to provide complex and various NRT services to a user. Byusing such a consumption model, an NRT service provider may generate auser interface that is interactive with NRT service (NDO or TDO) andtransmit it. The receiver 300 generates a look and feel user interfaceinteractive with a user on the basis of a plurality of content items inNRT service and provides it to a user. For this, a content item may bereferred to as an entry content item and for this, a scriptedconsumption model may be used as a consumption model.

FIG. 79 is a conceptual view illustrating an NRT service including anentry content item.

Referring to FIG. 79, the NRT service may include a plurality of contentitems such as a content item 0, a content item 1, and a content item 3.Also, a service provider may designate each entry content item or entryfile through the transmitter 200. As shown in FIG. 79, an entry contentitem is designated as the content item 0, and the entry file isdesignated as a file 0 and a file 5.

When an NRT service of FIG. 79 is received and a user selects it, thereceiver 300 executes the content item 0, i.e., an entry content itemfirst of all. When launching the content item 0, the receiver 300 mayexecute the file 0, i.e., an entry file, first of all. Here, the entrycontent item may include a function for managing other content items.Accordingly, the receiver 300 may display the content item 1 and thecontent item 3 by an operation of the content item 0, and the contentitem 0 may execute or terminates at least one of the content item 1 andthe content item 3 according to a user's selection. Moreover, when thecontent item 1 is executed, the file 5, i.e., an entry file, may belaunched first.

FIGS. 80 and 81 are views illustrating an NRT-IT to transmit informationon an entry content item.

The NRT-IT or NCT shown in FIGS. 80 and 81 is included in servicesignaling data, and the transmitter 200 includes information on an entrycontent item in service signaling data and transmits it.

As mentioned above, the NRT-IT may include individual information on aplurality of content items. Information of each of the plurality ofcontent items may be included in a content item loop starting as for(j=0; j<num_content_items_in_section; j++). Then, each content item maycorrespond to each content item loop identified by a content linkagefield. Accordingly, the receiver 200 parses a content item loop toobtain a no_entry_flag field corresponding to each content item. Sincedescriptions for other fields in FIGS. 80 and 81 are identical orsimilar to those of FIG. 16, their repeated descriptions are omitted.

A no_entry_flag field may be a 1-bit number indicating an entry contentitem. If this field is 0, a content item corresponding to a content itemloop that this field belongs may be an entry content item of a serviceidentified by service_id. If this field is 1, a content itemcorresponding to a content item loop that this field belongs may not bean entry content item of the above-mentioned service.

FIG. 82 is a view illustrating an operation method of the receiver 300when an entry content item is transmitted according to an embodiment ofthe present invention.

Referring to FIG. 82, the receiver 300 first receives an SMT and anNRT-IT from service signaling data in operation S8800, parses a servicelevel descriptor loop from the SMT, and parsesNRT_service_info_descriptor in the service level descriptor loop inoperation S8810.

Also, the receiver 300 obtains information on an NRT service transmittedbased on the parsed NRT service information descriptor, for example, atleast one of an application type, a service category, service capacity,and video or audio codec information, to generate service guide anddisplays it in operation S8820.

Then, the receiver 300 determines whether service reception on NRTservice is selected in operation S8830.

Moreover, when service reception on NRT service is selected, thereceiver 300 obtains reception information of content items that aservice to be received includes from an NRT-IT in operation S8840.

Then, the receiver 300 receives content items of an NRT servicetransmitted from the transmitter 200 on the basis of the obtainedcontent item reception information in operation S8850. The servicemanager 350 of the receiver 300 may receive files configuring contentitems in access to a FLUTE session on the basis of the obtainedservice_id field and content_linkage field, as mentioned above.

Then, the receiver 300 determines whether there is a execute command onthe received NRT service in operation S8860. The service manager 350 ofthe receiver 300 determines whether there is a user's execute commandwhen the content item of NRT service is received completely.Additionally, the service manager 350 may automatically execute thereceived NRT service without a user's execute command.

When the NRT service is executed, the receiver 300 first determineswhether a consumption model is scripted in operation S8870. When itsvalue is not a scripted consumption model, the receiver 300 operates ina different way according to another consumption model to provideservice in operation S8890.

However, when the consumption model field corresponds to a valuedesignated as a scripted consumption model, the receiver searches for anentry content item among the received content items in operation S8875.

Then, when the entry content item is searched, the receiver 300 executesan entry file first among files in the entry content item in operationS8880. When there is no entry file, the receiver 300 may execute a fileaccording to a file order or predetermined order.

Then, the receiver 300 operates by the executed file, and accordingly,provides NRT service to a user in operation S8885. The receiver 300provides NRT service by sing an interactive interface in an entrycontent item. Additionally, the receiver 300 may execute or manageanother content item according to a user input for an interactiveinterface in an entry content item.

In such a way, the receiver 300 executes an entry content item first toprovide an interactive interface to a user. The interactive interfacemay include a management menu such as execution, termination, storage,or deletion of NRT service. For this, the interactive interface mayinclude an icon image or video corresponding to each management menu. Auser may conveniently manage another NRT service or other content itemsthrough an interface in an entry content item.

According to an embodiment of the present invention, the transmitter 200generates a plurality of NRT service objects in correspondence to thesame NRT service, and allocates different consumption model field valuesto the generated NRT service objects. The transmitter 200 may includeallocation information of the consumption model field values in theabove-mentioned NRT service table and then, may transmit it.

FIG. 83 is a conceptual view of a plurality of NRT service objectstransmitted according to an embodiment of the present invention.

As shown in FIG. 83, an NRT service transmitted one virtual channel mayinclude an NRT service object A and an NRT service object B. Also, A andB may provide the same NRT service. However, the NRT service object Amay be designated as a browser and download consumption model and theNRT service object B may be designated as a scripted consumption model.

Here, the entry content item may refer to an NRT-IT or an SMT in orderto execute content items included in another NRT service. The NRT-IT orSMT may include relationship information between NRT services andinformation on content items according thereto. For example, the NRT-ITmay include relationship information or reference information that theNRT service A and the NRT service B provide services by using the samecontent item.

According to an embodiment, the NRT service A and the NRT service Bprovide service by using the same content item, but the NRT service Aand the NRT service B may include different NRT service objects orcontent items.

FIG. 84 is a view illustrating a syntax of an NRT service descriptorincluded in the SMT according to an embodiment of the present invention.

The above-mentioned relationship information may be included in an NRTservice descriptor in a service descriptor loop of the SMT. According toan embodiment of the present invention, service is provided using thesame content item but NRT services having different consumption modelfield values may be referred to as the same service or equivalentservice. The relationship information on the equivalent services, asshown in FIG. 84, may include an equivalent_service_not_present field, anum_equivalent_services field, and an equivalent_service_id field.

FIGS. 85 and 86 are views illustrating a syntax of another NRT-ITaccording to another embodiment of the present invention. Sincedescriptions for other fields of the NRT-IT of FIGS. 70 and 71 areidentical to the above, repeated descriptions are omitted.

As shown in FIGS. 80 and 86, the NRT-IT may further include anavailable_on_current_service field. When equivalent service istransmitted, this field indicates whether there is a content itemtransmitted in another NRT service. Additionally, even when there is noequivalent service, this field indicates whether a content item linkedwith a currently executed NRT service is transmitted through another NRTservice in order for the receiver 300 to receive or execute a contentitem of another NRT service through an entry content item.

The available_on_current_service field may be used for the receiver 300to determine whether there is a content item transmitted in another NRTservice linked with the currently transmitted NRT service.

FIG. 87 is a view illustrating a syntax of Other_NRT_location_descriptoraccording to another embodiment of the present invention.

Referring to FIG. 87, an other NRT location descriptor includes adescriptor_tag field, a descriptor_length field, anum_other_NRT_locations field, and an other_service_id field.

The receiver 300 determines whether a content item is transmittedthrough another NRT services on the basis of the NRT-IT, and obtains theidentifier of another NRT services in which a content item istransmitted on the basis of an NRT service location descriptor.

FIG. 88 is a flowchart illustrating a method of receiving broadcastservice according to an embodiment of the present invention.

Referring to FIG. 88, the receiver 300 receives an SMT and an NRT-ITfrom the service signaling data in operation S8900, parses a servicelevel descriptor loop from the SMT and parsesNRT_service_info_descriptor in the service level descriptor loop inoperation S8910, generates service guide on the basis of the parsed NRTservice info descriptor and displays it in operation S8920, anddetermines whether service reception for NRT service is selected inoperation S8930. The above operations may be performed by the servicemanager 350 of the receiver 300.

Moreover, when service reception on NRT service is selected, thereceiver 300 obtains reception information of content items that aservice to be received includes from the NRT-IT in operation S8940. Thereception information on content items may include content_linkage of acontent item and service_id of NRT service that each content itembelongs.

Then, the receiver 300 first determines whether a content item isprovided through NRT service by using the reception information inoperation S8950. Here, the reception information of a content item mayinclude relationship information indicating whether a content item istransmitted through a currently selected service or whether a contentitem is transmitted through another NRT services. For example, thereception information may include the available_on_current_servicefield. Additionally, when a content item is transmitted through anotherNRT service, the reception information of the content item may includethe identifier of the other NRT service and the identifier of thecontent item in order to receive the content item. Accordingly, thereceiver 300 determines whether a content item is provided throughanother NRT service by using the relationship information.

Additionally, the relationship information may includeother_NRT_location_descriptor, and the service manager 350 of thereceiver 300 determines whether a content item of NRT service that acurrent user selects to receive is transmitted through a selectedservice or another NRT service by using the relationship information,and identifies an object corresponding to the other NRT service toreceive a content item therein.

If it is determined that the content item is not transmitted throughanother NRT service, the service manager 350 of the receiver 300accesses a FLUTE session according to the obtained content itemreception information, and receives files configuring each content itemthrough the above method.

Moreover, if it is determined that the content item is transmitted, theservice manager 350 of the receiver 300 obtains the service identifierfor another NRT service from the reception information in operationS8960 and, by receiving SMT and NRT-IT corresponding thereto, obtainscontent item reception information in another NRT service in operationS8970. Then, the service manager 350 may receive files configuring acontent item in access to a FLUTE session on the basis of the contentitem reception information.

Hereinafter, an adjunct service receiving method according to anotherembodiment of the present invention will be described.

The adjunct service may include service information, metadata, enhanceddata, a compiled execution file, web application, Hypertext MarkupLanguage (HTML) document, XML document, cascading style sheet (CSS)document, an audio file, a video file, and an address such as UniformResource Locator (URL). Additionally, the adjunct service may includesignaling data, real time data, a trigger, an SMT, an NRT-IT, an EIT, aVCT, and a PMT.

As digital broadcasting is vitalized, a broadcasting station transmitsmain AV content together with adjunct service data that are used inlinkage with the main AV content or separated from the main AV content.

However, under the current broadcasting environment, an image displaydevice in each home may less likely receive broadcast signals directlythrough airwaves. Rather, since an image display device in each home isconnected to a broadcast receiving device such as a settop box, it mayplay an uncompressed AV content that the broadcast receiving deviceprovides.

Furthermore, the broadcast receiving device receives content from aserver called a multichannel video programming distributor (MVPD). Afterreceiving a broadcast signal from a broadcasting station and extractingcontent from the received broadcast signal, the MVPD converts theextracted content into a signal of a format fit for transmission andprovides the converted signal to the broadcast receiving device. In thisprocess, since the MVPD excludes the extracted adjunct service data oradds another adjunct service data, a broadcasting station may only serveas a role providing AV content and thus, may not provide an adjunctservice led by a broadcasting station.

Since only uncompressed AV data are provided to an image display deviceby extracting main AV data from signals that are received from abroadcast receiving device or an MVPD, adjunct service is available onlyunder a control of a broadcast receiving device and no adjunct serviceis available under a control of an image display device. This mayprevent a broadcasting station from providing a self-led adjunct servicefurther more.

Furthermore, even when a broadcasting station provides an adjunctservice through a wireless channel, no adjunct service may be providedsufficiently due to the limitations of a bandwidth.

Hereinafter, an image display device providing an adjunct service led bya broadcasting station and a control method thereof will be described.

Then, a network topology according to an embodiment of the presentinvention will be described with reference to FIGS. 89 to 97.

FIG. 89 is a block diagram of a network topology according to anembodiment of the present invention.

As shown in FIG. 89, the network topology according to an embodiment ofthe present invention includes a content providing server 10, a contentrecognition service providing server 20, a multichannel videodistribution server 30, an adjunct service information providing server40, a plurality of adjunct service providing servers 50, a settop box60, a network 70, and a receiver 300.

The content providing server 10 may correspond to a broadcastingstation, and broadcasts a broadcast signal including main audio-visualcontent. The broadcast signal may further include an adjunct service.The adjunct service may or may not relate to a main audio-visualcontent. At least one content providing server may exist.

The content recognition service providing server 20 provides a contentrecognition service that allows the receiver 300 to recognize content onthe basis of the main audio-visual content. The content recognitionservice providing server 20 may or may not modify the main audio-visualcontent. At least one content recognition service providing server mayexist.

The content recognition service providing server 20 may be a watermarkserver inserting a visible watermark looking like a logo into the mainAV content by applying a modification on the main audio-visual content.This watermark server may watermark the logo of a content provider atthe top left or top right of each frame of the main AV content.

Moreover, the content recognition service providing server 20 may be awatermark server inserting content information as invisible watermarkinto the main audio-visual content by applying a modification on themain AV content.

Moreover, the content recognition service providing server 20 may be afingerprint server extracting and storing feature information from someframes of the main AV content or a section of audio samples of the mainAV content. This feature information is called a signature.

The multichannel video distribution server 30 receives broadcast signalsfrom a plurality of broadcasting stations and multiplexes them toprovide the multiplexed signals to the settop box 60. Especially, themultichannel video distribution server 30 performs a demodulation andchannel decoding operation on the received broadcast signals to extracta main AV content and an adjunct service, and then performs a channelencoding operation on the extracted main AV content and adjunct serviceto generate multiplexed signals. At this point, since the multichannelvideo distribution server 30 excludes the extracted adjunct service dataor adds another adjunct service data, a broadcasting station may notprovide a service led by the broadcasting station. At least onemultichannel video distribution server may exits.

The settop box 60 tunes a channel selected by a user, receives a signalof the tuned channel, and performs a demodulation and channel decodingoperation on the received signal to extract main audio-video content.Then, the settop box 60 decodes the extracted main AV content by usingH.264/Moving Picture Experts Group-4 advanced video coding (MPEG-4 AVC),Dolby AC-3, and a Moving Picture Experts Group-2 Advanced Audio Coding(MPEG-2 AAC) algorithm, so as to generate uncompressed main AV content.The settop box 60 provides the generated uncompressed main AV content tothe receiver 300 through an external input port of the receiver 300.

The adjunct service information providing server 40 provides adjunctservice information for at least one available adjunct service relatingto main AV content in response to a request of the receiver 300. Theadjunct service information providing server 40 and the receiver 300 maycommunicate with each other through the network 70. At least one adjunctservice address providing server may exist. The adjunct serviceinformation providing server 40 may provide adjunct service informationfor an adjunct service having the highest priority among a plurality ofavailable adjunct services.

The adjunct service providing server 50 provides at least one adjunctservice used in relation to main AV content in response to a request ofthe receiver 300. At least one adjunct service providing server mayexist. The adjunct service providing server 50 and the receiver 300 maycommunicate with each other through the network 70.

The network 70 may be an IP based network or an Advanced TelevisionSystems Committee—Mobile/Handheld (ATSC M/H) channel.

The receiver 300 may be a device having a display unit such as atelevision, a notebook, a mobile phone, a smart phone, etc. The receiver300 may receive uncompressed main AV content from the settop box 60through an external input port, or may receive a broadcast signalincluding encoded main AV content from the content providing server 10or the multichannel video distribution server 30 through a broadcastnetwork. The receiver 300 may receive a content recognition service fromthe content recognition service providing server 20 through the network70, may receive an address of at least one available adjunct servicerelating to main AV content from the adjunct service informationproviding server 40 through the network 70, or may receive at least oneavailable adjunct service relating to main AV content from the adjunctservice providing server 50 through the network 70.

At least two of the content providing server 10, the content recognitionservice providing server 20, the multichannel video distribution server30, the adjunct service information providing server 40, and theplurality of adjunct service providing servers 50 may be combined as aform of one server or operated by one provider.

FIG. 90 is a block diagram of a watermark based network topologyaccording to an embodiment of the present invention.

As shown in FIG. 90, the network topology according to an embodiment ofthe present invention further includes a watermark server 21.

The watermark server 21 shown in FIG. 90 applies a modification on mainAV content to insert content information into the main AV content. Themultichannel video distribution server 30 receives and distributes abroadcast signal including the modified main AV content. Especially, thewatermark server may use a digital watermarking technology describedbelow.

The digital watermark is a process for inserting information into adigital signal through a method of making deletion hard. For example,the digital signal may be audio, photo, or video. When this digitalsignal is copied, the inserted information is also contained in thecopy. One digital signal may carry different several watermarkssimultaneously.

In visible watermarking, the inserted information is distinguishable bythe eye in photo or video. Typically, the inserted information is a textor logo identifying an owner of media. When a television broadcastingstation adds its logo to the corner of a transmitted video, this is avisually identifiable watermark.

In invisible watermarking, although information is added as digital datain audio, photo, or video, the fact that a predetermined amount ofinformation is hidden may be detected but such information may not berecognized. A secrete message may be delivered through the invisiblewatermarking.

One application of watermarking is a copyright protection system forpreventing illegal copy of digital media. For example, a copy deviceobtains a watermark from digital media before copying the digital media,and determines whether to copy the digital media on the basis of thecontent of the watermark.

Another application of watermarking is a source trace of digital media.A watermark is embedded in digital media at each point on a distributionpath. When such digital media are found later, a watermark may beextracted from the digital media, and the source of distribution may berecognized from the content of the watermark.

Description on digital media is another application of invisiblewatermarking.

A file format for digital media includes additional information calledmetadata, and a digital watermark is distinguished from metadata in thatthe digital water mark is delivered as a visual signal itself of digitalmedia.

A watermarking method includes spread spectrum, quantization, andamplitude modulation.

When a marked signal is obtained by additional modification, thewatermarking method corresponds to the spread spectrum. Although thespread spectrum watermark is known to be quite robust, since thewatermark interferes with an embedded host signal, a large amount ofinformation is not loaded.

When a marked signal is obtained by the quantization, the watermarkingmethod corresponds to a quantization type. Although the quantizationwatermark is less robust, a large amount of information is loaded.

When a marked signal is obtained through an additional modificationmethod similar to the spread spectrum in a space domain, thewatermarking method corresponds to the amplitude modulation.

FIG. 91 is a ladder diagram illustrating a data flow in a watermarkbased network topology according to an embodiment of the presentinvention.

First, the content providing server 10 transmits a broadcast signalincluding main AV content and adjunct service in operation S101A.

The watermark server 21 receives a broadcast signal that the contentproviding server 10 provides, inserts a visible watermark looking like alogo into main AV content by applying a modification on the main AVcontent, inserts watermark information as invisible watermark into mainAV content, and provides the watermarked main AV content and adjunctservice to the MVPD 30 in operation S103A.

The watermark information inserted through an invisible watermark mayinclude at least one of watermark purpose, content information, adjunctservice information, and available enhance service. The watermarkpurpose may include one of illegal copy prevention, audience survey, andadditional service acquisition.

The content information may include at least one of identificationinformation of a content provider providing main AV content, main AVcontent identification information, main AV content rating information,time information of a content interval used for content informationacquisition, the name of a channel broadcasting main AV content, thelogo of a channel broadcasting main AV content, the name of a channelbroadcasting main AV content, a usage information report address, ausage information report period, and a minimum usage time for usageinformation acquisition.

When the receiver 300 uses a watermark to obtain content information,time information of a content interval used for content informationacquisition may be time information of a content interval where awatermark is embedded. When the receiver 300 uses a fingerprint toobtain content information, time information of a content interval usedfor content information acquisition may be time information of a contentinterval where feature information is extracted. The time information ofa content interval used for content information acquisition may includeat least one of a start time of a content interval used for contentinformation acquisition, a duration of a content interval used forcontent information acquisition, and an end time of a content intervalused for content information acquisition.

The usage information report address may include at least one of a mainAV content viewing information report address and an adjunct serviceusage information report address. The usage information report periodmay include at least one of a main AV content viewing information reportperiod and an adjunct service usage information report period. Theminimum usage time for usage information acquisition may include atleast one of a minimum viewing time for main AV content viewinginformation acquisition and a minimum usage time for adjunct serviceusage information extraction.

On the basis of the case that main AV content is watched more than aminimum viewing time, the receiver 300 may obtain the viewinginformation of the main AV content, and may report the extracted viewinginformation to the main AV content viewing information report addressduring the main AV content viewing information report period.

On the basis of the case that adjunct service is used more than aminimum usage time, the receiver 300 may obtains adjunct service usageinformation and may report the extracted usage information to theadjunct service usage information report address during the adjunctservice usage information report period.

The adjunct service information may include at least one of informationon whether adjunct service exits, an adjunct service address providingserver address, an acquisition path of each available adjunct service,an address for each available adjunct service, a start time of eachavailable adjunct service, an end time of each available adjunctservice, a lifetime of each available adjunct service, an acquisitionmode of each available adjunct service, a request period for eachavailable adjunct service, priority information of each availableadjunct service, description of each available adjunct service, acategory of each available adjunct service, a usage information reportaddress, and a minimum usage time for usage information acquisition.

An acquisition path of available adjunct service may indicate an IPbased network or an Advanced Television SystemsCommittee—Mobile/Handheld (ATSC M/H) channel. In the case that theacquisition path of available adjunct service is the ATSC M/H, theadjunct service information may further include frequency informationand channel information. The acquisition mode of each available adjunctservice may indicate Push or Pull.

Moreover, the watermark server 21 may insert watermark information as aninvisible watermark into the logo of main AV content.

For example, the watermark server 21 may insert a barcode into apredetermined position of a logo. At this point, the predeterminedposition of the logo may correspond to the first bottom line of an areawhere the logo is displayed. When receiving the main AV contentincluding a logo with a bar code inserted, the receiver 300 may notdisplay the bar code.

Moreover, the watermark server 21 may insert watermark information as ametadata form of the logo. At this point, the form of the logo may bemaintained.

Moreover, the watermark server 21 may insert N bit watermark informationinto the logo of M frames. That is, the watermark server 21 may insertM*N watermark information through M frames.

The MVPD 30 receives a broadcast signal including the watermarked mainAV content and adjunct service and generates a multiplexed signal toprovide it to the settop box 60 in operation S105A. At this point, themultiplexed signal may exclude the received adjunct service or mayinclude new adjunct service.

The settop box 60 tunes a channel that a user selects and receives asignal of the tuned channel, demodulates the received broadcast signaland performs channel decoding, performs AV decoding to generateuncompressed main AV content, and then, provides the generateduncompressed main AV content to the receiver 300 in operation S106A.

Moreover, the content providing server 10 also broadcasts a broadcastsignal including main AV content through a wireless channel in operationS107A.

Additionally, the MVPD 30 may transmit a broadcast signal including mainAV content to the receiver 300 directly without going through the settopbox 60 in operation S108A.

The receiver 300 may receive uncompressed main AV content through thesettop box 60. Or, the receiver 300 may receive a broadcast signalthrough a wireless channel, and may demodulates and decode the receivedbroadcast signal to obtain main AV content. Or, the receiver 300 mayreceive a broadcast signal from the MVPD 30, and may demodulate anddecode the received broadcast signal to receive main AV content. Thereceiver 300 extracts watermark information from some frames of theobtained main AV content or a section of audio samples of the obtainedmain AV content. When the watermark information corresponds to a logo,the receiver 300 confirms a watermark server address corresponding tothe logo extracted from a corresponding relationship between a pluralityof logos and a plurality of watermark server addresses. When thewatermark information corresponds to the logo, the receiver 300 may notidentify main AV content by only using the logo. Moreover, when thewatermark information does not include content information, the receiver300 may not identify main AV content but the watermark information mayinclude content provider identification information or a watermarkserver address. When the watermark information includes content provideridentification information, the receiver 300 may confirm a watermarkserver address corresponding to the content provider identificationinformation extracted from a corresponding relationship between aplurality of content identification information and a plurality ofwatermark server addresses. In such a manner, when main AV contentcannot be identified by using only the watermark information, thereceiver 300 accesses the watermark server 21 corresponding to theobtained watermark server address to transmit a first query in operationS109A.

The watermark server 21 provides a first response to the first query inoperation S111A. The first response may include at least one of contentinformation, adjunct service information, and available enhance service.

If the watermark information and the first response do not include anadjunct service address, the receiver 300 may not obtain adjunctservice. However, the watermark information and the first response mayinclude an adjunct service address providing server address. In such amanner, if the receiver 300 does not obtain an adjunct service addressor adjunct service through the watermark information and the firstresponse but obtains an adjunct service address providing serveraddress, it accesses the adjunct service information providing server 40corresponding to the obtained adjunct service address providing serveraddress to transmit a second query including content information inoperation S119A.

The adjunct service information providing server 40 searches for atleast one available adjunct service relating to the content informationof the second query. Then, the adjunct service information providingserver 40 provides adjunct service information for at least oneavailable adjunct service to the receiver 300 through a second responseto the second query in operation S121A.

If the receiver 300 obtains at least one available adjunct serviceaddress through the watermark information, the first response, or thesecond response, it accesses the at least one available adjunct serviceaddress to request adjunct service in operation S123A and obtains theadjunct service in operation S125A.

FIG. 92 is a view illustrating a watermark based content recognitiontiming according to an embodiment of the present invention.

As shown in FIG. 92, when the settop box 60 is turned on and tunes achannel and the receiver 300 receives a main AV content of the tunedchannel from the settop box 60 through an external input port 311, thereceiver 300 detects a content provider identifier (or a broadcastingstation identifier) from the watermark of the main AV content. Then, thereceiver 300 may detect content information from the watermark of themain AV content on the basis of the detected content provideridentifier.

At this point, as shown in FIG. 92, the detection available period ofthe content provider identifier and the detection available period ofthe content information may be different from each other. Especially,the detection available period of the content provider identifier may beshorter than the detection available period of the content information.Through this, the receiver 300 may have an efficient configuration fordetecting only necessary information.

FIG. 93 is a block diagram of a fingerprint based network topologyaccording to an embodiment of the present invention.

As shown in FIG. 93, a network topology according to an embodiment ofthe present invention further includes a fingerprint server 22.

The fingerprint server 22 shown in FIG. 93 does not apply a modificationon main AV content, and extracts feature information from some frames ofthe main AV content or a section of audio samples of the main AV contentand stores it. Then, on receiving the feature information from thereceiver 300, the fingerprint server 22 provides the identifier and timeinformation of the AV content corresponding to the received featureinformation.

FIG. 94 is a ladder diagram illustrating data flow in a fingerprintbased network topology according to an embodiment of the presentinvention.

First, the content providing server 10 transmits a broadcast signalincluding main AV content and adjunct service in operation S201A.

The fingerprint server 22 receives the broadcast signal that the contentproviding server 10 provides, extracts a plurality of featureinformation from a plurality of frames of the main AV content or aplurality of sections of audio samples of the main AV content,establishes a database for a plurality of query results corresponding tothe plurality of feature information, respectively, in operation S203A.The query result may include at least one of content information,adjunct service information, and available enhance service.

The MVPD 30 receives a broadcast signal including main AV content andgenerates a multiplexed signal to provide it to the settop box 60 inoperation S205A. At this point, the multiplexed signal may exclude thereceived adjunct service or may include new adjunct service.

The settop box 60 tunes a channel that a user selects and receives asignal of the tuned channel, demodulates the received broadcast signaland performs channel decoding, performs AV decoding to generateuncompressed main AV content, and then, provides the generateduncompressed main AV content to the receiver 300 in operation S206A.

Moreover, the content providing server 10 also broadcasts a broadcastsignal including main AV content through a wireless channel in operationS207A.

Additionally, the MVPD 30 may transmit a broadcast signal including mainAV content to the receiver 300 directly without going through the settopbox 60 in operation S208A.

The receiver 300 may receive uncompressed main AV content through thesettop box 60. Or, the receiver 300 may receive a broadcast signalthrough a wireless channel, and may demodulates and decode the receivedbroadcast signal to obtain main AV content. Or, the receiver 300 mayreceive a broadcast signal from the MVPD 30, and may demodulate anddecode the received broadcast signal to receive main AV content. Thereceiver 300 extracts feature information from some frames of theobtained main AV content or a section of audio samples of the obtainedmain AV content in operation S213A.

The receiver 300 accesses the fingerprint server 22 corresponding to apredetermined fingerprint server address to transmit a first queryincluding the extracted feature information in operation S215A.

The fingerprint server 22 provides a query result as a first response tothe first query in operation S217A. If the first response is failed, thereceiver 300 accesses the fingerprint server 22 corresponding to anotherfingerprint server address to transmit the first query including theextracted feature information.

The fingerprint server 22 may provide Extensible Markup Language (XML)document as the query result. The XML document containing the queryresult will be described with FIG. 7 and Table 1.

FIG. 95 is an XML schema diagram of ACR-Resulttype containing a queryresult according to an embodiment of the present invention.

As shown in FIG. 95, ACR-Resulttype containing a query result includes aResultCode attribute and ContentID, NTPTimestamp,SignalingChannelInformation, and ServiceInformation elements.

Table 5 shows an XML Schema of ACR-ResultType containing this queryresult.

TABLE 5 <xs:complexType name=“ACR-ResultType”>   <xs:sequence>   <xs:element name=“ContentID” type=“xs:anyURI”/>    <xs:elementname=“NTPTimestamp” type=“xs:unsignedLong”/>    <xs:elementname=“SignalingChannelInformation”>     <xs:complexType>     <xs:sequence>       <xs:element name=“SignalingChannelURL”maxOccurs=“unbounded”>        <xs:complexType>        <xs:simpleContent>          <xs:extension base=“xs:anyURI”>          <xs:attribute name=“UpdateMode”>            <xs:simpleType>            <xs:restriction base=“xs:string”>             <xs:enumeration value=“Pull”/>              <xs:enumerationvalue=“Push”/>             </xs:restriction>            </xs:simpleType>          </xs:attribute>           <xs:attribute name=“PollingCycle”type=“xs:unsignedInt”/>          </xs:extension>        </xs:simpleContent>        </xs:complexType>       </xs:element>     </xs:sequence>     </xs:complexType>    </xs:element>   <xs:element name=“ServiceInformation”>     <xs:complexType>     <xs:sequence>       <xs:element name=“ServiceName”type=“xs:string”/>       <xs:element name=“ServiceLogo” type=“xs:anyURI”minOccurs=“0”/>       <xs:element name=“ServiceDescription”type=“xs:string” minOccurs=“0” maxOccurs=“unbounded”/>     </xs:sequence>     </xs:complexType>    </xs:element>    <xs:anynamespace=“##other” processContents=“skip” minOccurs=“0”maxOccurs=“unbounded”/>   </xs:sequence>   <xs:attributename=“ResultCode” type=“xs:string” use=“required”/>   <xs:anyAttributeprocessContents=“skip”/>  </xs:complexType>

As the ContentID element, an ATSC content identifier shown in Table 6below may be used.

TABLE 6 Syntax The Number of bits format ATSC_content_identifier( ) { TSID 16  uimsbf  reserved 2 bslbf  end_of_day 5 uimsbf  unique_for 9uimsbf  content_id var }

As shown in Table 6, the ATSC content identifier has a structureincluding a TSID and a house number.

As the ContentID element, a Global Service Identifier for ATSC-M/Hservice described below may be used.

Moreover, as a ContentID element, an ATSC content identifier describedbelow may be used.

Hereinafter, FIG. 94 will be described again.

If a query result does not include an adjunct service address or adjunctservice but includes an adjunct service address providing serveraddress, the receiver 300 accesses the adjunct service informationproviding server 40 corresponding to the obtained adjunct serviceaddress providing server address to transmit a second query includingcontent information in operation S219A.

The adjunct service information providing server 40 searches for atleast one available adjunct service relating to the content informationof the second query. Then, the adjunct service information providingserver 40 provides adjunct service information for at least oneavailable adjunct service as a second response to the second query tothe receiver 300 in operation S221A.

If the receiver 300 obtains at least one available adjunct serviceaddress through the first response or the second response, it accessesthe at least one available adjunct service address to request adjunctservice in operation S223A and obtains the adjunct service in operationS225A.

If the UpdateMode attribute has a Pull value, the receiver 300 transmitsan HTTP request to the adjunct service providing server 50 throughSignalingChannelURL, and in response to this, receives an HTTP responseincluding PSIP binary stream from the adjunct service providing server50. In this case, the receiver 300 may transmit an HTTP requestaccording to a Polling period designated by a PollingCycle attribute.Additionally, the SignalingChannelURL element may have an update timeattribute. In this case, the receiver 300 may transmit an HTTP requestat an update time designated by an update time attribute.

If the UpdateMode attribute has a Push value, the receiver 300 mayreceive an update from a server asynchronously by utilizing anXMLHTTPRequest API. After the receives 300 transmits an asynchronousrequest to a server through an XMLHTTPRequest object, if there is achange in signaling information, the server provides signalinginformation through this channel in response to the request. If there isa restriction on a waiting time of a session, a session timeout responseis generated, and a receiver recognizes the generated session timeoutresponse immediately to transmit a request again, so that a signallychannel between the receiver and the server may be maintained at alltimes.

FIG. 96 is a block diagram of a fingerprint based network topologyaccording to an embodiment of the present invention.

As shown in FIG. 96, a network topology according to an embodiment ofthe present invention further includes a watermark server 21 and afingerprint server 22.

The watermark server 21 shown in FIG. 96 inserts content provideridentification information into main AV content. The watermark server 21may insert content provider identification information as a watermarklooking like a logo into main AV content, or may insert content provideridentification information as an invisible watermark into main AVcontent.

The fingerprint server 22 does not apply a modification on main AVcontent, and extracts feature information from some frames of the mainAV content or a section of audio samples of the main AV content andstores it. Then, on receiving the feature information from the receiver300, the fingerprint server 22 provides the identifier and timeinformation of the AV content corresponding to the received featureinformation.

FIG. 97 is a ladder diagram illustrating data flow in a watermark andfingerprint based network topology according to an embodiment of thepresent invention.

First, the content providing server 10 transmits a broadcast signalincluding main AV content and adjunct service in operation S301A.

The watermark server 21 receives a broadcast signal that the contentproviding server 10 provides, inserts a visible watermark looking like alogo into main AV content by applying a modification on the main AVcontent, inserts watermark information as invisible watermark into mainAV content, and provides the watermarked main AV content and adjunctservice to the MVPD 30 in operation S303A. The watermark informationinserted through an invisible watermark may include at least one ofcontent information, adjunct service information, and available enhanceservice. The content information and the adjunct service information arethe same as described above.

The MVPD 30 receives a broadcast signal including the watermarked mainAV content and adjunct service and generates a multiplexed signal toprovide it to the settop box 60 in operation S305A. At this point, themultiplexed signal may exclude the received adjunct service or mayinclude new adjunct service.

The settop box 60 tunes a channel that a user selects and receives asignal of the turned channel, demodulates the received broadcast signaland performs channel decoding, performs AV decoding to generateuncompressed main AV content, and then, provides the generateduncompressed main AV content to the receiver 300 in operation S306A.

Moreover, the content providing server 10 also broadcasts a broadcastsignal including main AV content through a wireless channel in operationS307A.

Additionally, the MVPD 30 may transmit a broadcast signal including mainAV content to the receiver 300 directly without going through the settopbox 60 in operation S308A.

The receiver 300 may receive uncompressed main AV content through thesettop box 60. Or, the receiver 300 may receive a broadcast signalthrough a wireless channel, and may demodulates and decode the receivedbroadcast signal to obtain main AV content. Or, the receiver 300 mayreceive a broadcast signal from the MVPD 30, and may demodulate anddecode the received broadcast signal to receive main AV content. Thereceiver 300 extracts watermark information from some frames of theobtained main AV content or a section of audio samples of the obtainedmain AV content. When the watermark information corresponds to a logo,the receiver 300 confirms a watermark server address corresponding tothe logo extracted from a corresponding relationship between a pluralityof logos and a plurality of watermark server addresses. When thewatermark information corresponds to the logo, the receiver 300 may notidentify main AV content by only using the logo. Moreover, when thewatermark information does not include content information, the receiver300 may not identify main AV content but the watermark information mayinclude content provider identification information or a watermarkserver address. When the watermark information includes content provideridentification information, the receiver 300 may confirm a watermarkserver address corresponding to the content provider identificationinformation extracted from a corresponding relationship between aplurality of content identification information and a plurality ofwatermark server addresses. In such a manner, when main AV contentcannot be identified by using only the watermark information, thereceiver 300 accesses the watermark server 21 corresponding to theobtained watermark server address to transmit a first query in operationS309A.

The watermark server 21 provides a first response to the first query inoperation S311A. The first response may include at least one of afingerprint server address, content information, adjunct serviceinformation, and available enhance service. The content information andthe adjunct service information are the same as described above.

If the watermark information and the first response include afingerprint server address, the receiver 300 extracts featureinformation from some frames of the main AV content or a section ofaudio samples of the main AV content in operation S313A.

The receiver 300 accesses the fingerprint server 22 corresponding to thefingerprint server address in the first response to transmit a secondquery including the extracted feature information in operation S315A.

The fingerprint server 22 provides a query result as a second responseto the second query in operation S317A.

If a query result does not include an adjunct service address or adjunctservice but includes an adjunct service address providing serveraddress, the receiver 300 accesses the adjunct service informationproviding server 40 corresponding to the obtained adjunct serviceaddress providing server address to transmit a third query includingcontent information in operation S319A.

The adjunct service information providing server 40 searches for atleast one available adjunct service relating to the content informationof the third query. Then, the adjunct service information providingserver 40 provides adjunct service information for at least oneavailable adjunct service to the receiver 300 through a third responseto the third query in operation S321A.

If the receiver 300 obtains at least one available adjunct serviceaddress through the first response, the second response, or the thirdresponse, it accesses the at least one available adjunct service addressto request adjunct service in operation S323A and obtains the adjunctservice in operation S325A.

Then, a receiver 300 according to an embodiment of the present inventionwill be described with reference to FIG. 98.

As shown in FIG. 98, the receiver 300 according to an embodiment of thepresent invention includes a broadcast signal receiving unit 301, ademodulation unit, 310, a channel decoding unit 305, a demultiplexingunit 320, an AV decoding unit 309, an external input port 311, aplayback control unit 313, a playback device 320, a service manager 350,a data transceiving unit, and a memory 350.

The broadcast signal receiving unit 301 receives a broadcast signal fromthe content providing server 10 or the MVPD 30.

The demodulation unit 310 generates a demodulated signal by demodulatingthe received broadcast signal.

The channel decoding unit 305 generate channel-decoded data bychannel-decoding the demodulated signal.

The demultiplexing unit 310 separates main AV content and adjunctservice from the channel-decoded data. The separated adjunct service isstored in the adjunct service storage unit 352.

The AV decoding unit 309 AV decodes the separated main AV content togenerate uncompressed main AV content.

Moreover, the external input port 311 receives uncompressed main AVcontent from the settop box 60, a digital versatile disk (DVD) player,and a Blu-ray disk player. The external input port 311 may include atleast one of a DSUB port, a High Definition Multimedia Interface (HDMI)port, a Digital Visual Interface (DVI) port, a composite port, acomponent port, and an S-Video port.

The playback control unit 313 plays at least one of an uncompressed mainAV content generated by the AV decoding unit 309 or an uncompressed mainAV content received from the external input port 311, in the playbackdevice 320 in response to a user selection.

The playback device 320 includes a display unit 321 and a speaker 323.The display unit 321 may include at least one of a liquid crystaldisplay (LCD), a thin film transistor-liquid crystal display (a TFTLCD), an organic light-emitting diode (OLED), a flexible display, and a3D display.

The service manager 350 obtains content information of main AV content,and obtains available adjunct service on the basis of the obtainedcontent information. Especially, as described above, the service manager350 may obtain identification information of main AV content on thebasis of some frames of the uncompressed main AV content or a section ofaudio samples of the uncompressed main AV content, and this is called anautomatic contents recognition (ACR) in the specification.

The service manager 350 corresponds to the service manager 350 of FIG.34.

The data transceiving unit 341 may include an Advanced TelevisionSystems Committee—Mobile/Handheld (ATSC-M/H) channel transceiving unit341 a and an IP transceiving unit 341 b.

The ATSC-M/H channel transceiving unit 341 a communicates with anotherdevice or server through an ATSC-M/H channel.

The IP transceiving unit 341 b communicates with another device orserver through an IP based network.

The memory 350 may include at least one type of storage medium among aflash memory type, a hard disk type, a multimedia card micro type, cardtype memory (for example, SD or XD memory), Random Access Memory (RAM),Static Random Access Memory (SRAM), Read-Only Memory (ROM), ElectricallyErasable Programmable Read-Only Memory (EEPROM), Programmable Read-OnlyMemory (PROM), magnetic memory, magnetic disk, and optical disk. Thereceiver 300 may operate in relation to a web storage performing thestorage function of the memory 350 on internet.

The memory 350 may include a content information storage unit 351, anadjunct service storage unit 352, a logo storage unit 353, a settinginformation storage unit 354, a bookmark storage unit 355, a userinformation storage unit 356, and a usage information storage unit 357.

The content information storage unit 351 stores a plurality of contentinformation corresponding to a plurality of feature information.

The adjunct service storage unit 352 may store a plurality of adjunctservices corresponding to a plurality of feature information or maystore a plurality of adjunct services corresponding to a plurality ofcontent information.

The logo storage unit 353 stores a plurality of logos. Also, the logostorage unit may further store a content provider identifiercorresponding to a plurality of logos or a watermark server addresscorresponding to a plurality of logos.

The setting information storage unit 354 stores setting information forACR.

The bookmark storage unit 355 stores a bookmark.

The user information storage unit 356 stores user information. The userinformation may include at least one of at least one account informationfor at least one service, local information, family member information,preferred genre information, image display device information, and ausage information providing range. The at least one account informationmay include account information for usage information measurement serverand account information of social network service such as twitter andfacebook. The local information may include address information and azip code. The family member information may include the number of familymembers, each member age, each member sex, each member religion, andeach member job. The preferred genre information may be set with atleast one of sports, movies, drama, education, news, entertainment, andother genres. The image display device information may includeinformation on an image display device type, a manufacturer, a firmwareversion, a resolution, a model name, OS, a browser, storage deviceexistence, a capacity of a storage device, and network speed. Once theusage information providing range is set, the receiver 300 collects andreports main AV content viewing information and adjunct service usageinformation within a set range. The usage information providing rangemay be set with respect to each virtual channel. Additionally, a usageinformation measurement allowable range may be set with respect to anentire physical channel.

The usage information storage unit 357 stores main AV content viewinginformation and adjunct service usage information collected by thereceiver 300. Moreover, the receiver 300 analyzes a service usagepattern on the basis of the collected main AV content viewinginformation and the collected adjunct service usage information, andstores the analyzed service usage pattern in the usage informationstorage unit 357.

The service manager 350 obtains the content information of main AVcontent from the fingerprint server 22 or the content informationstorage unit 351. If there is no content information corresponding tothe extracted feature information or sufficient content information inthe content information storage unit 351, the service manager 350 mayreceive additional content information through the data transceivingunit 341. Moreover, the service manager 350 may update contentinformation continuously.

The service manager 350 obtains available adjunct service from theadjunct service providing server 50 or the adjunct service storage unit353. If there is no adjunct service or sufficient adjunct service in theadjunct service storage unit 353, the service manager 350 may updateadjunct service through the data transceiving unit 341. Moreover, theservice manager 350 may update adjunct service continuously.

The service manager 350 extracts a logo from main AV content and queriesthe logo storage unit 355 to obtain a content provider identifier orwatermark server address corresponding to the extracted logo. If thereis no logo corresponding to the extracted logo or sufficient logo in thelogo storage unit 355, the service manager 350 may receive an additionallogo through the data transceiving unit 341. Moreover, the servicemanager 350 may update the logo continuously.

The service manager 350 may perform various methods to reduce the burdenof calculation while a logo extracted from main AV content is comparedto a plurality of logos in the logo storage unit 355.

For example, the service manager 350 may perform a comparison operationon the basis of color characteristics. That is, the service manager 350compares the color characteristic of an extracted logo with the colorcharacteristic of a logo in the logo storage unit 355, so that it isdetermined whether they are matched to each other.

Furthermore, the service manager 350 may perform a comparison operationon the basis of character recognition. That is, the service manager 350compares the character of an extracted logo with the character of a logoin the logo storage unit 355, so that it is determined whether they arematched to each other.

Furthermore, the service manager 350 may perform a comparison operationon the basis of the outline form of a logo. That is, the service manager350 compares the outline form of an extracted logo with the outline formof a logo in the logo storage unit 355, so that it is determined whetherthey are matched to each other.

The service manager 350 obtains content information of main AV contenton the basis of some frames of the uncompressed main AV content and asection of audio samples of the uncompressed main AV content, obtainssignaling data for adjunct service on the basis of the obtained contentinformation, and then, obtains adjunct service on the basis of thesignaling data.

Moreover, hereinafter, in providing the above-described trigger service,a method of transmitting a trigger through an internet protocol (IP)based network will be described.

When a trigger is transmitted through an IP based network, thetransmitter 200 may include trigger in the above-described TDO triggertable and transmit it. Accordingly, the receiver 300 may obtain atrigger on the basis of the TDO trigger table.

In the case of using a TDO trigger table, in order to transmit a TDOtrigger table through an IP based network, the transmitter 200 may storethe TDO trigger table in a specific location on an IP based networkfirst and may transmit the location information of the TDO trigger tableon a network to the receiver 300. For example, the receiver 300 mayreceive the URL information of the TDO trigger table, access theposition of the TDO trigger table on the network on the basis of the URLinformation of the received TDO trigger table, and receive the TDOtrigger table through the IP based network. In this case, the TDOtrigger table may have a syntax format of a private section structureidentical to that of a table transmitted through a broadcast network,and accordingly, the receiver 300 may receive and process a trigger byusing an existing module without additional technical implementation forobtaining a trigger and processing trigger information.

Moreover, when a trigger is transmitted through an IP based network, thetransmitter 200 may generate the above-described trigger in XML formatand then may transmit it to the receiver 300.

FIG. 99 is a view illustrating an XML format of a trigger according toan embodiment of the present invention. FIGS. 100 and 101 are viewsillustrating an XML format of a trigger according to an embodiment ofthe present invention.

Such a content-items element may indicate a content item, that is, atrigger target object, or other content items distinguished from it.

The above content items element may be used when a content itemcorresponding to a TDO is transmitted through an NRT service.

Additionally, the content items element may be used when a content itemis transmitted through an IP network. As described above, the receiver300 may identify content items corresponding to a TDO transmittedthrough an IP network on the basis of a combination of the Service-IDRef attribute value and the content linkage attribute value.

Additionally, the above-mentioned content URL element may be used when afile configuring a content item is transmitted through an IP network.

Then, the content URL element may include a relative URL or an absolutetag URI. When a content URL element is designated as a relative URL oran absolute tag URI, the transmitter 200 may transmit a content itemonly through a FLUTE session used in an NRT service by using thedesignated URL or URI. For example, when a content URL element includesa relative URL or an absolute tag URI, the receiver 300 may receive acontent item from a broadcast network connected through a FLUTE by usingthe URL or URI. Moreover, when a content URL element does not include arelative URL or an absolute tag URI, the receiver 300 may receive acontent item from at least one of an IP network and a broadcast networkon the basis of the content URL element.

In such a manner, according to a trigger structure defined in an XMLformat, a trigger may include essential and various information forproviding a TDO service and may provide effective transmission throughan IP network.

Moreover, when such a trigger is transmitted through an IP network, thetransmitter 200 may transmit signaling information (trigger signalinginformation) so to allow the receiver 300 to obtain a trigger. Thetrigger signaling information may include location information on an IPnetwork through which a trigger is transmitted, for example, trigger URLinformation. Additionally, the trigger signaling information may betransmitted in different formats according to a transmission network.

In some cases, the receiver 300 may be directly connected to only an IPnetwork or may be directly connected to both a broadcast network and anIP network. Accordingly, the transmitter 200 may transmit signalinginformation for trigger acquisition through at least one of a broadcastnetwork or an IP network. For this, at least one transmission andreception method may be used.

First, when the receiver 300 directly receives a broadcast signalthrough a broadcast network, trigger signaling information may betransmitted through a broadcast network. In this case, the triggersignaling information may be included in a trigger URL descriptor or aTDO trigger table and transmitted through a broadcast network.

FIG. 102 is a view illustrating a syntax of a trigger URL descriptoraccording to an embodiment of the present invention.

Such a trigger descriptor may be included in at least one of a PSIPtable, an SMT, and an NRT-IT and transmitted through an IP network or abroadcast network. For example, the receiver 300 may extract the triggerdescriptor from at least one of a PSIP table, an SMT, and an NRT-IT, andbased on this, may obtain location information of a trigger on an IPnetwork, and may receive the trigger transmitted through the IP network.

FIG. 103 is a view illustrating a syntax of a TDO trigger tableaccording to an embodiment of the present invention.

Accordingly, on receiving a TDO trigger table, the receiver 300 mayparse each field and obtain location information of a trigger on an IPnetwork on the basis of the parsed trigger URL information, and mayreceive the trigger transmitted through the IP network.

Moreover, the receiver 300 may not be directly connected to broadcastnetwork but may be connected to an IP network. In this case, thereceiver 300 may obtain a trigger or trigger signaling informationincluded in an adjunct service by using the above-described adjunctservice receiving method.

Even when the receiver 300 is not directly connected to a broadcastnetwork and is connected to a broadcast receiver such as a settop box,it may receive adjunct service data used in linkage with main AV contenttransmitted from a broadcasting station, that is, the transmitter 200,or independent of the main AV content. Also, the receiver 300 may obtaina trigger included in the adjunct service data or may receiving atrigger through an IP network by using the adjunct service data.

FIG. 104 is a view illustrating an operating method of the receiver 300according to an embodiment of the present invention.

Referring to FIG. 104, the receiver 300 plays content in operationS9001. Referring to FIG. 104, the receiver 300 may not be directlyconnected to a broadcast network and may receive and play anuncompressed AV content provided from a broadcast receiver. In thiscase, the receiver 300 may play AV content but may not directly receivetrigger information transmitted from the transmitter 200 through abroadcast network. Accordingly, the receiver 300 may use theabove-described adjunct service receiving method.

The receiver 300 confirms whether there is an adjunct service for theplayed content in operation S9003. The service manager 350 of thereceiver 300 may identify the content by using a portion of the contentbeing played through a method of using a watermark described withreference to FIG. 91 or a method of using the fingerprint server 22described with reference to FIG. 94, and may confirm that there is anadjunct service for the content. Additionally, the service manager 350of the receiver 300 determines whether a trigger is included in theconfirmed adjunct service.

For example, the receiver 300 may determine whether there is a triggeron the basis of a query result for AV content received from thefingerprint server 22. Additionally, the receiver 300 may determinewhether there is a trigger through the method of using a watermarkdescribed with reference to FIG. 91.

For example, the receiver 300 may obtain trigger URL information fromthe data of ACR-Resulttype containing a query result received from thefingerprint server 22. The trigger URL information may include URLinformation for receiving a trigger. For example, the trigger URLinformation may include specific position information in a triggerserver located on an IP network.

FIG. 105 is a view illustrating an XML schema diagram of ACR-Resulttypecontaining a query result according to another embodiment of the presentinvention.

The triggerURL element may include URL information for receiving atrigger linked with a content identified by the query result. Thereceiver 300 may request a plurality of triggers after a specific timeof the identified content from a trigger server on the basis of thetrigger URL element and NTPTimestamp and its detailed operation isdescribed later.

When a trigger is included in an adjunct service, the receiver requestsat least one trigger included in the adjunct service from a server inoperation S9005. The request target server may be called a triggerserver and a trigger may be transmitted to the receiver 300 through anIP network. Additionally, the trigger server may include a serverdirectly accessible through an IP network among the above-describedadjunct service providing server 50, adjunct service informationproviding server 40, contents providing server 10, fingerprint server 22and watermark server 21.

The service manager 350 of the receiver 300 may designate a time rangeas requesting a trigger from a trigger server.

The time range may include a specific time segment. The specific timesegment or time range may be designated by time information of a contentinterval used for content information acquisition. The time informationof a content interval may be time information of a content intervalwhere a watermark is embedded or time information of a content intervalwhere feature information is extracted. Additionally, a specific timesegment or time range designated at the trigger request may bedesignated on the basis of query result information obtained through anoperation of using a watermark or a fingerprint. For example, thereceiver 300 may designate a time segment of a trigger to be requestedbased on NTP Timestamp included in the above-mentioned ACR-Resulttype.

Then, the receiver 300 receives trigger request result informationcorresponding to the request in operation S9007

As described above, the receiver 300 may receive trigger request resultinformation from a trigger server in response to a trigger requesttransmitted to the trigger server. The trigger request resultinformation may include at least one trigger. Accordingly, the receiver300 may obtain a trigger from the trigger request result informationreceived from the trigger server.

Then, the receiver 300 performs a trigger action on a trigger targetobject at a trigger time in operation S9009. The receiver 300 mayperform a trigger action on a trigger target object at a trigger time onthe basis of a trigger time, a trigger action, and trigger target objectinformation included in the obtained trigger.

FIG. 106 is a flowchart illustrating a trigger requesting and receivingmethod of the receiver 300 according to an embodiment of the presentinvention.

Referring to FIG. 106, the receiver 300 according to an embodiment ofthe present invention obtains a trigger URL in operation S9011, requestsa trigger in a specific time segment linked with a content on the basisof the obtained URL in operation S9013, and receives a trigger requestresult corresponding to the trigger request from the server in operationS9015.

As described above, the receiver 300 may obtain the URL of a triggerlinked with the content on the basis of some intervals of a contentbeing played. Additionally, the receiver 300 may obtain time informationon the some segments, for example, a timestamp, on the basis of somesegments of a content being played. Then, the receiver 300 may request atrigger in a specific time segment linked with a content from a triggerserver on the basis of the obtained trigger URL and timestamp.

When requesting a trigger on the basis of the trigger URL, the receiver300 may generate a request message by using a hyper Text TransferProtocol (HTTP) and may transmit the generated request message to thetrigger server through an IP network. The trigger server may receive theHTTP based request message and generate a trigger request result in anHTTP Response format in response thereto to transmit it to the receiver300.

For example, when time information or a timestamp is not included in aquery result received from the fingerprint server 22 or it is determinedthat a time segment of a trigger is not necessarily specified, thereceiver 300 may generate a trigger request message including a triggerURL by using a GET command format used in HTTP and then may transmit itto the trigger server. In this case, the trigger server may include allcurrently transmittable triggers or a list of all triggers in the HTTPresponse and may transmit them to the receiver 300.

Additionally, if a time segment needs to be specified, the receiver 300may request a trigger in a specific time segment by using an HTTP GETcommand format or an HTTP POST command format. The trigger URL and thespecific time segment may be determined based on the trigger URL and thetimestamp included in ACR Resulttype, for example.

In relation to the trigger URL and the Timestamp included in ACRResulttype, the trigger URL may be obtained in the format ofhttp://www.atsc2.com/content1/trigger and the Timestamp may be obtainedin the time format of 2011/06/28T18:00:00. Such a trigger URL andTimestamp may correspond to a content segment (for example, somesegments of a content being played) used for content informationacquisition through the above-described fingerprint or watermark.

Here, the receiver 300 may generate a trigger request message by usingthe HTTP GET command format.

FIG. 107 is a view illustrating an HTTP GET command format based triggerrequest message according to an embodiment of the present invention.

The GET command format used in HTTP may include a URL segment in themessage header thereof. The trigger request message may include thetrigger URL in such a URL segment.

Additionally, the GET command format used in HTTP includes a timestampfield and a duration field following the URL segment. In the HTTP GETcommand format, the timestamp field may indicate the start time of aspecific segment and the duration field may include time lengthinformation of the specific segment. The time length may be expressed ina second unit. For example, the receiver 300 may generate a messagerequesting a trigger in a time segment within 30 min (600 sec) after thetimestamp on the basis of the trigger URL and the timestamp included inthe obtained ACR Resulttype. As shown in FIG. 107, the trigger URL andthe time segment included in such a request message may be expressed ashttp://www.atsc2com/content1/trigger?timestamp=2011%2F06%2F28T18%3A00%3A00&duration=600. Accordingly, in the trigger request messageof the HTTP GET format according to an embodiment of the presentinvention, the time segment may be designated astimestamp=2011/06/28T18:00:00 according to the format of name=value.

FIG. 108 is a view illustrating an HTTP POST command format basedtrigger request message according to an embodiment of the presentinvention.

Like the HTTP GET command format, the POST command format used in HTTPmay include a URL segment in the message header and the trigger requestmessage may include the trigger URL in such a URL segment and mayinclude an additional timestamp field in a message body. In the HTTPPOST command format according to an embodiment of the present invention,like HTTP GET, the timestamp field may indicate the start time of aspecific segment and the duration field may include time lengthinformation of the specific segment. The time length may be expressed ina second unit.

For example, the receiver 300 may generate a message requesting atrigger in a time segment within 30 min (600 sec) after the timestamp onthe basis of the trigger URL and the timestamp included in the obtainedACR Resulttype. The trigger URL and the time segment included in such arequest message may be expressed as shown in FIG. 108. In the case ofHTTP POST, the time segment may be designated astimestamp=2011/06/28T18:00:00 according to the format of name=value.

In such a manner, the receiver 300 may generate a trigger requestmessage including the trigger URL and time segment information accordingto the HTTP GET or POST command format and may transmit it to thetrigger server. The HTTP command format may be an efficient informationrequest method used on an IP network. Accordingly, the receiver 300 maytransmit the trigger request message through an IP network by using theHTTP GET or POST command format.

Moreover, the trigger server may generate a trigger request resultmessage according to the trigger request message received from thereceiver 300 and may transmit it to the receiver 300.

Here, the trigger request result message may include a trigger and mayinclude list information of triggers that a trigger server is capable ofproviding.

Additionally, a trigger may be provided in plurality and if the numberof triggers is equal to or greater than a predetermined value, thetrigger server may divide and transmit a plurality of triggers bydividing a time segment. Accordingly, the trigger request result messagemay include trigger time segment information of triggers currentlytransmitted from a trigger server. Then, a difference between a timesegment of triggers that the trigger server is capable of providing anda time segment that the receiver 300 requests may occur. Accordingly,trigger time segment information included in a trigger request resultmessage may be identical to or different from a time segment included ina trigger request message.

FIGS. 109 and 110 are views illustrating an XML schema diagram of atrigger request result message according to an embodiment of the presentinvention.

As shown in FIGS. 109 and 110, the trigger request result message mayhave an XML format and may include a trigger in the above-described XMLformat.

According to an embodiment, a TDO-triggers element included in thetrigger request result message may include at least one of a fromattribute, a to attribute, and a TimeOffset attribute and theTDO-trigger element may include at least one of a from attribute and ato attribute.

The from attribute and to attribute fields included in the TDO-triggerselement may indicate a time segment of triggers included in the triggerrequest result. For example, if a trigger time of triggers included in atrigger request result is an segment between A to B, the from attributevalue may be A and the to attribute value may be B.

Then, the from attribute and to attribute fields included in theTDO-triggers element may indicate a specific time segment according to atrigger time of triggers corresponding to a specific service amongtriggers included in the trigger request result. If a trigger time oftriggers corresponding to a specific service is a segment between A toB, the from attribute value may be A and the to attribute value may beB. Here, if the TDO-triggers element indicate different from and toattribute values, the from attribute and to attribute values of theTDO-trigger element may override the from attribute and to attributevalues of the TDO-triggers element.

Moreover, as shown in FIG. 109, the TDO-triggers element may include aTimeOffset attribute field. The TimeOffset attribute field may indicatea waiting time for waiting for the next trigger request. The triggerserver may receive a trigger request message from a plurality ofreceivers 300 and overload due to the increase of a trigger requestmessage may occur. Accordingly, the trigger server may performdistribution at a predetermined time segment by limiting a triggerrequest message transmission time of each receiver 300 by using theTimeOffset attribute field. For example, the receiver 300 may obtain atime range of currently received triggers by extracting the fromattribute and to attribute fields from the trigger request resultmessage, obtain waiting time information by extracting the TimeOffsetattribute field, and wait for a predetermined time until the nexttrigger request message transmission. Such a waiting time may bedesignated by a trigger server. The trigger server may designate anadditional TimeOffset value to each receiver 300. Additionally, thetrigger server may instruct the receiver 300 to wait for a random timewithin a TimeOffset time segment by using the trigger request resultmessage. When a random time waiting is instructed in the trigger requestresult message, the receiver 300 determines a random time within a timesegment of 0 to TimeOffset, and may wait for the next trigger requestmessage transmission

Moreover, the flowchart of FIG. 106 is described with reference to FIGS.109 to 110.

Then, the receiver 300 obtains time segment information and waiting timeinformation from the received trigger request result in operation S9017

As described above, the receiver 300 may receive a trigger requestresult message in an HTTP response format from a trigger server. Such atrigger request result message may have the XML format shown in FIGS.109 to 110, and may include a plurality of triggers in an XML format.

Then, the trigger request result message, as described above, mayinclude information on a time segment at which the plurality of triggersare to be executed and may include waiting time information on the nexttrigger request message transmission.

Then, the receiver 300 transmits the next trigger request message to thetrigger server after a predetermined time on the basis of waiting timeinformation in operation S9019.

As described above, the trigger request result message may includewaiting time information.

Accordingly, the receiver 300 may wait for a predetermined time on thebasis of the waiting time information that the trigger request resultmessage instructs and may generates the next trigger request messageafter a predetermined time to transmit it to the trigger server.Accordingly, if there are a plurality of receivers 300, the networktraffic may be reduced as the transmission of a trigger request messageis distributed.

Moreover, the receiver 300 may generate the next trigger request messagefor a time segment not currently received on the basis of the fromattribute and the to attribute included in the trigger request resultmessage and then may transmit it to the trigger server.

In such a way, since the receiver 300 continuously receives a triggerwhose time segment is designated through a communication with a triggerserver, more efficient trigger transmission may be provided and anadjunct service for broadcast service according thereto may beefficiently provided.

Moreover, when a content item is a declarative object (DO) such as anNDO or a TDO, information on the DO including various parameters forallowing the receiver 300 to control the DO may be represented usingcontent_descriptor of an NRT-IT. Especially, content_descriptor mayinclude additional metadata for such a DO and content_descriptorincluding metadata for a DO may be referred to as a DO descriptor.

FIG. 111 is a view illustrating a DO descriptor according to anembodiment of the present invention.

As shown in FIG. 111, the DO descriptor may include a descriptor tag, adescriptor length, a DO identifier, a DO version, a test DO, a visibleUI, a handles configuration changed, a handles externally controlledviceo, a persistent storage field.

The receiver 300 may obtain additional metadata for DO signaled throughan NRT-IT through each field of such a DO descriptor and may manage andcontrol a DO on the basis of this.

The receiver 300 may uniquely identify each DO by using DO_identifier.Then, the receiver 300 may load a previously stored DO for specificchannel into another channel by using DO_identifier. If a broadcastingstation owns a plurality of channels or virtual channels, especially, itmay use the DO identifier usefully. Additionally, even if a DO is usedonly in one channel, in the case that the DO is used for long periods oftime, the DO is identifiable regardless of a transmission session.

test_do may be a flag indicating that a corresponding DO is used fortest purpose.

visible_UI may be a 1-bit unsigned integer indicating whether a DO has avisible UI.

persistent_storage may represent a storage space required for a DO. Ifthe space is insufficient, the receiver 300 may not execute acorresponding DO or may execute a corresponding DO in a state limitingsome functions and may notify space insufficiency to a user.

Moreover, the transmitter 200 may transmit an acquisition type of timeslot descriptor corresponding to a content item or file configuring anNRT service.

Hereinafter, a time slot descriptor configured according to anembodiment of the present invention will be described with reference toFIG. 112.

FIG. 112 is a view illustrating a bit stream syntax of a time slotdescriptor configured according to an embodiment of the presentinvention. FIG. 113 is a view illustrating contents of sub fields of atime slot descriptor.

Referring to FIGS. 112 and 113, the transmitter 200 may generate anacquisition type time slot descriptor to insert it into a content leveldescriptor loop of an NRT-IT. At this point, at least one acquisitiontype time slot descriptor may exist in a content level descriptor loop.Each time interval encoded by the acquisition type time slot descriptorrepresents a time for acquiring a corresponding content item.

Referring to FIG. 113, the time slot parameter field time_slot_params ofthe acquisition type time slot descriptor may include an acquisitiontime parameter acquisition_time. The acquisition time parameterrepresents a minimum time interval length necessary for guaranteeingthat at least one complete content item instance is transmitted during acorresponding time interval.

According to another embodiment of the present invention, thetransmitter 200 may generate a presentation type time slot descriptor toinsert it in a content level descriptor loop of an NRT-IT. At thispoint, at least one presentation type time slot descriptor may exist ina content level descriptor loop. The presentation type time slotdescriptor may signal that a corresponding time slot represents a timeinterval at which a corresponding content item is presented.

Hereinafter, a time slot descriptor of a TDO enable type configuredaccording to another embodiment of the present invention will bedescribed with reference to FIG. 113.

According to another embodiment of the present invention, thetransmitter 200 may generate a TDO enable type time slot descriptor toinsert it in a content level descriptor loop of an NRT-IT.

In such a manner, the receiver 300 may obtain the file of acorresponding content item through a FLUTE session at a time of when anacquisition slot of a corresponding content item exists, on the basis ofthe time slot parameter information. The receiver 300 recognizes whenthe file of a corresponding content item is obtained by recognizing anacquisition interval of a corresponding content item through anacquisition slot. For example, the receiver 300 may obtain the file of acorresponding content item during a time based on the obtained timeparameter information, from an arbitrary time in an acquisition intervalof the corresponding content item recognized. At this point, asdescribed with reference to FIG. 24, the receiver 300 reads an FDT in acorresponding FLUTE session and receives a corresponding file or objectif a Content-ID attribute field on a corresponding file is identical toa corresponding content item identifier content_id.

Moreover, all TDOs and NDOs may belong to at least one applicationdomain. An application domain may be represented by at least one fullyqualified domain name (FQDN). The FQDN may be configured in a prefixform of all files or pages configuring a TDO or an NDO.

For example, a basic application domain that a TDO or an NDO belongs maybe designated as a FQDN for an entry file of an NRT content itemconfiguring the TDO or the NDO. When the entry file does have an FQDN(for example, content-location in a FLUTE FDT corresponding to an entryfile has a relative URI value instead of an absolute URI), the receiver300 may obtain an application boundary descriptorapplication_boundary_descriptor from a descriptor loop of an NRT-IT foran NRT content item corresponding to the entry file.

The application boundary descriptor may be included in an NRT-IT and mayhave a form defined in DAB standard TS102 809. For example, theapplication boundary descriptor may include at least one URI setincluding a fully qualified domain name of an application domain for aTDO or an NDO.

Accordingly, the receiver 300 may determine that any documents loadedfrom the outside of an application domain designated for a TDO or an NDOare unreliable. For example, the receiver 300 may prevent any HTML orECMA script files received from the outside of an application domainfrom being loaded on the basis of the application boundary descriptor.

FIG. 114 is a view illustrating an application boundary descriptoraccording to an embodiment of the present invention.

Referring to FIG. 114, an application boundary descriptor according toan embodiment of the present invention may include a descriptor tag, aboundary extension count, a boundary extension length, and a boundaryextension byte.

The boundary extension byte boundary_extension_byte) may include atleast one URL in a URL prefix form. The receiver 300 may determine thatall URLs matching the prefix are included in an application boundarythat the application boundary descriptor represents. For example, theURI prefix may include a strict prefix. Accordingly, the URI prefix mayinclude ‘http://www.example.com’ instead of ‘www.example.com’ and mayinclude a path of a component such as ‘http://www.example.com/epg/’. Thereceiver 300 may obtain a platform specification on the basis of aminimum level of granularity given by this prefix.

In such a way, the transmitter 200 may signal at least one applicationdomain through an application boundary descriptor according to anembodiment of the present invention. In this case, the receiver 300 mayset an application domain obtained first as a basic application domain.

Moreover, the transmitter 200 may signal an application domain to thereceiver 300 by using a DO descriptor suggested in an embodiment of thepresent invention, besides such an application boundary descriptor.

FIG. 115 is a view illustrating a DO descriptor extended according toanother embodiment of the present invention.

Referring to FIG. 115, a DO descriptor extended according to anotherembodiment of the present invention may further include an applicationdomain count, an application domain length, and application domain bytefields, besides the above-described fields.

An application domain byte application_domain_byte may be a fieldincluding at least one URL in a URL prefix form indicating anapplication domain. The receiver 300 may determine that all URLsmatching the prefix are included in an application boundary that the DOdescriptor represents. For example, the URI prefix may include a strictprefix. Accordingly, the URI prefix may include ‘http://www.example.com’instead of ‘www.example.com’ and may include a path of a component suchas ‘http://www.example.com/epg/’. The receiver 300 may obtain a platformspecification on the basis of a minimum level of granularity given bythis prefix.

In such a way, the transmitter 200 may signal at least one applicationdomain through a DO descriptor according to another embodiment of thepresent invention. In this case, the receiver 300 may set an applicationdomain obtained first as a basic application domain.

The receiver 300 may obtain application domain information on the basisof such a DO descriptor. The receiver 300 may perform an authoritymanagement on DO execution according to the application domaininformation. Accordingly, the receiver 300 may deny access according tothe application domain information when a resource that a DO attempts toaccess is located out of a range of an application domain designated bythe application domain information. Additionally, when a resource that aDO attempts to access is located out of a range of a designatedapplication domain, the receiver 300 may allow access and may processthe access as entering into an untrusted domain, thereby preventing theaccess to a resource in an application domain

Moreover, as described above, the receiver 300 may receive an adjunctservice on a channel during current viewing through an IP by using anautomatic contents recognition (ACR). The adjunct service may includeATSC 2.0 content to be serviced in the further, for example.

Accordingly, the adjunct service may include a URL of a content serversuch as a start point for obtaining ATSC content and a trigger, includea virtual channel identifier that the content server recognizes, andinclude a time stamp for at least one broadcast frame of a last watchedchannel.

Then, the adjunct service may include a signaling table. The signalingtable may include an SMT, an NRT-IT, a Text fragment table (TFT), aPurchase Item table (PIT) indicating purchase available content items,and a Purchase Terms and Channels table (PTCT) indicating purchase andchannel terms, and also may include an internet locations table (ILT)described later.

Such signaling tables may correspond to a service signaling channel ofeach virtual channel. For example, each of other tables other than anNRT-IT and a TFT may correspond to one service signaling channel.Additionally, each one NRT-IT may exist in correspondence to each NRTservice included in each virtual channel. The NRT-IT may be configuredwith various lengths of continuous NRT-IT instances and may cover aplurality of time intervals starting from a current time interval.Additionally, a TFT may selectively appear in correspondence to each NRTservice. The TFT may be configured with continuous TFT instances toone-to-one correspond to an NRT-IT instance for the service.

Then, after obtaining the above-described URL and channel identifier,the receiver 300 may receive an adjunct service through an IP in thefollowing way.

First, the receiver 300 may receive a signaling table from a contentserver on the basis of the obtained URL. For example, the receiver 300may receive an NRT-IT instance and a TFT instance covering a currenttime interval. Additionally, the receiver 300 may receive an NRT-ITinstance and a TFT instance covering the next time interval. Thereceiver 300 may access a TDO relating to a currently playing program byusing the received instance.

Then, the receiver 300 may receive a necessary content item on the basisof URLs in the received NRT-IT.

Additionally, the receiver 300 may receive a trigger stream on the basisof URLs in an internet location table (ILT).

FIG. 116 is a view illustrating an ILT according to an embodiment of thepresent invention.

Referring to FIG. 116, the ILT may be transmitted from a content serverand may include a locations defined field, a URL function code field,and a URL field.

The URL function code field may represent functions of a URL. Forexample, when the URL function code is 000, the function of a URL may bedata collection or may represent a parameter used for another website ordelivered for activating a TDO. Additionally, when the URL function codeis 001, this may represent a URL providing a trigger stream.

Accordingly, the receiver 300 may perform audience reporting or triggerstream reception on the basis of the URL of such as a locations definedfield. Such an ILT may be transmitted through a service signalingchannel or an IP. By transmitting a URL through a newly defined tablesuch as an ILT, the URL may be transmitted at a relatively less cyclefrequency as compared to when the URL is included in the descriptor ofan SMT and transmitted and a bandwidth used in a very low level may besaved.

Then, a service designated by the URL may be a usage reporting serverfor audience survey. Such a usage reporting server may be a serveraddress for performing usage reporting on Linear TV service/NRTservice/NRT Content item (including a TDO) included in a virtual channelin a service signaling channel corresponding to a currently viewingchannel. In this case, an ILT may be configured with a table where onlyURLs designated to have the same URL_Function_code are bound or a tablewhere all URLs are provided to have a plurality of URL_Function_codevalues. For example, the receiver 300 may classify an ILT includingtrigger stream URLs as Internet Location Table Triggers (ILT-Trig) andmay classify a table including the URL of a usage reporting server asInternet Location Table Usage reporting (ILT-Usage).

Moreover, in order to transmit such an adjunct service through internet,a transmission method using HTTP may be used. As defined in IETFstandard RFC 6062, an HTTP transmission method may include HTTP ShortPolling, HTTP Long Polling, and HTTP Streaming.

Among them, in order to transmit a trigger among adjunct servicesthrough internet, HTTP Short Polling or HTTP Streaming may be used.

In the case of HTTP Short Polling, the receiver 300 may transmit an HTTPrequest to a server during a predetermined interval. The server mayreturn update in response to each request until the last request beforeHTTP connection termination. When a time interval becomes longer, adelay time that a receiver obtains update may become very longer. If thetime interval is short, the unnecessary overhead of a messagetransmitted between a client and a server may be increased when HTTP/TCPconnection starts and ends.

Such HTTP Short Polling may be useful when it is possible to know atrigger activation time in advance, like a previously recordedbroadcast.

Moreover, in the case of HTTP Streaming, when the receiver 300 transmitsan initial request to a server, the server opens HTTP/TCP connectionpersistent at each update and transmits a response configured with adata stream. In this case, a delay time for obtaining update may becomeshorter and overhead may be reduced, but HTTP/TCP connection needs to beopened all the time.

Then, HTTP Streaming may be useful when it is impossible to know atrigger activation time in advance, like a live broadcast.

Accordingly, when a trigger is transmitted through HTTP Short Polling orHTTP Streaming, the URL of a transfer server may be included in theabove-described adjunct service, a trigger, or the above-described ILTin the form of a URL. When the receiver 300 obtains the URL of a serverin any way, signaling tables corresponding to an image being playedbased on the URL may be received through internet by using HTTP ShortPolling or HTTP Streaming.

According to an embodiment of the present invention, the receiver 300may transmit a signaling table request to a server continuously on thebasis of an HTTP polling method and may obtain the updated signalingtable from the server.

FIG. 117 is a view illustrating a query table (Query terms for SignalingTable Requests) of a signaling table according to an embodiment of thepresent invention.

As shown in FIG. 117, the receiver 300 may request at least onesignaling table of an SMT, current or next NRT-IT and TFT instances,ILT/Usage, ILT/Trig, PIT, and PTCT.

When a query method is described with reference to FIG. 117, a firstquery may start with ?<chan_id>. Here, chan_id may represent the channelnumber of a virtual channel. chan_id may include a decimal notation formof a major channel number for a specific virtual channel and the periodmay follow the notation. A decimal notation form of a minor channelnumber for the virtual channel may follow the period.

Then, the query may include <svc_id>. Svc_id may represent the serviceidentifier of a specific NRT service. The service identifier may berepresented by a decimal notation of a high order byte, the period, anda decimal notation of a low order byte in order.

Moreover, in order to reduce the overhead according to a repeatedsignaling table request, a table set may be included in a table request.Such a table set may be expressed as a BASIC SET as shown in FIG. 117,for example.

For example, the receiver 300 may request a basic set from a signalingtable request message. When receiving the request, a server may transmitthe latest version of all basic tables. For example, the basic table mayinclude at least one of an SMT, a current NRT-IT, a current TFT, anILT/Usage, an ILT/Trig, a PIT, and a PICT and may allocate various setsaccording to service provider's convenience.

Moreover, the receiver 300 may obtain the address of a servertransmitting such a signaling table through various methods and that is,an ACR method according to an embodiment of the present invention may beused but the present invention is not limited thereto.

Then, the receiver 300 may request a signaling table for a virtualchannel or an NRT service to be received on the basis of such a querytable.

Upon receipt of a signaling table request according to a query tablefrom the receiver 300, the server may return a corresponding table ortable instance in response to the request. Here, the returned table ortable instance may be identical to those transmitted through a broadcaststream.

Then, when the table or table instance includes a plurality of sections,a table or table instance returned as one response from a server mayhave a form in which the plurality of sections are connected.

Then, upon receipt of a requested table, the receiver 300 may obtainsignaling information relating to all data from the table, which isidentical to that received from a broadcast through an antenna.Accordingly, the receiver 300 may obtain metadata for all NRT service,content items, and triggers relating to broadcast. Additionally, thereceiver 300 may obtain location information on files configuring allcontent times on the basis of the obtained metadata and may receive allfiles through internet connection. Then, the receiver may obtainlocation information that a trigger stream is transmitted on the basisof the obtained metadata and may receive a trigger stream throughinternet connection on the basis of the obtained trigger stream locationinformation.

Moreover, when only such an HTTP Polling method is used, a large numberof HTTP requests may cause heavy loads on the server. For this,according to an embodiment of the present invention, an improvementmethod using HTTP streaming may be suggested.

First, the receiver 300 may receive whether to update or an updatedsignaling table through HTTP streaming while receiving the latestversion of a signaling table through HTTP Polling.

For example, the receiver 300 may determine whether to update byseparately accessing a URL notifying whether to update through an HTTPstreaming method while receiving a signaling table through an HTTPpolling method. Such a Service Signaling Channel Update streaming URLmay be separately transmitted from a server, for example, through anInternet Location Table. In this case, URL_Function_Code may be assignedto 002.

Additionally, for example, the receiver 300 may use an HTTP Pollingmethod in the case of the first access and after that, an updated tablemay be received through HTTP streaming. A URL for receiving an updatedtable may be separately transmitted and for example, may be transmittedthrough an ILT.

Second, the receiver 300 may receive an event each time there is anupdated table with a session opened continuously through HTTP streaming.When the receiver 300 accesses the server first, the server may transmitall the latest version of signaling tables and then may transmit onlyupdated signaling tables.

Then, a server for delivering a signaling table or whether to update atable through HTTP Streaming, the server may transmit the followingevent form of a message.

An Updated_table_info event may represent a list of updated tables. Thisevent data may have the following form.

table_name>[;<table_version>] [, . . . ]: table_name may represent thename of an updated table. The table name may be identical to the queryterm shown in FIG. 117 for HTTP Polling. Additionally, the version of anupdated table may be selectively shown through a semicolon and severalnumber of updated tables may be shown by commas.

An updated_table event may represent an updated table itself and a tableupdated together with this event may be immediately delivered to thereceiver 300. In this case, the event data may include updated tables ina binary form as they are and in the case of a plurality of tables,sequentially attached tables may be delivered to the receiver 300.Moreover, in order to include this event in an HTTP response, tables maybe encoded in a URL encoding form by a server and then may betransmitted.

A table_name event may represent the name of an updated table by a tableunit. In this case, the receiver 300 determines that the received eventdata is an updated table for a table having the same name as an eventname. The event data may be encoded in a URL encoding form by a serverand then may be transmitted.

Additionally, as described above, the receiver 300 may request a tableand also a trigger through an HTTP polling method or may request themthrough HTTP GET or HTTP POST. Since detailed descriptions for this areidentical to those of FIGS. 106 to 110, overlapping descriptions areomitted.

Moreover, the activation time stamp of a trigger transmitted throughinternet may be determined relative to a server side time.

For example, a time that the receiver 300 starts to capture an AVsegment may be tn msec relative from a system time reference specifictiming of the receiver 300. Then, when a start time from a specifictiming on the basis of a broadcast time of an AV segment received from aserver is tb msec relatively, the time of the receiver 300 and thebroadcast time may have a difference of tn−tb. Then, when the activationtime stamp of a trigger received from internet is tx (measured based ona broadcast time), the trigger activation time determined by thereceiver 300 may be tx+(tn−tb) or tn+(tx−tb).

Accordingly, the receiver 300 may be required to request a time stamprelating to the server side time periodically while a trigger isrequested through internet. Accordingly, the receiver 300 according toan embodiment of the present invention may synchronize a local time withthe server side time and may activate a trigger at an appropriate time.

A request/response relationship of a trigger or signaling table throughinternet between the receiver 300 and a server according to anembodiment of the present invention is as follows.

First, at the HTTP request, upon receipt of an HTTP GET requestincluding a base URL through a virtual channel, a server (for example, acontent server) may transmit a trigger to the receiver 300 throughinternet correspondingly.

Such an HTTP GET request may include virtual channel identificationinformation, start time information, and duration information and mayhave the following format.

chan=<chan_id>&start=<start_time>[&duration=<duration>]

chan_id may represent the channel number of a virtual channel and mayinclude a decimal notation of a major channel number and a minor channelnumber divided by a period.

start_time may represent milliseconds in decimal form. The start timemay be relative to a server side time and may represent a start time ofa requested time interval.

Duration may represent a time interval of seconds in decimal form.Duration may represent a length of a time interval requested to thereceiver 300 when a content server uses a Short Polling method as atransmission method for a requested channel.

For example, the receiver 300 may designate a current time to start_timeduring request message transmission. When a content server in a Shortpolling mode receives the request message and responds to the receiver300, the receiver 300 transmits the next request before a time intervalend covered by the response so that it may receive the next responsebefore the time interval end. At this point, the receiver 300 maydesignate a time interval end time of a previous response to start_timeand then may transmit it. Accordingly, request and response transmissionmay be provided with a seamless interval.

Additionally, a server may transmit a response message to the receiver300 through HTTP Streaming in addition to HTTP Short Polling. The servermay operate in two modes and according to the two modes, a transmittedresponse may include trigger length data represented by an 8-bitunsigned integer and trigger activation time data represented by a32-bit unsigned integer. The trigger activation time, as describedabove, may be designated based on a server side time. A plurality oftriggers cannot be duplicated in one response message. Additionally,when an asynchronous trigger is included in a response message, thereceiver 300 may determine a time at which a trigger appears first in abroadcast stream received after start_time of a request message as anactivation time.

Moreover, according to an embodiment of the present invention, thereceiver 300 may add text/stream-event to an Accept header in an HTTPrequest header so that it notifies the server that it may receive anevent in an HTTP streaming form.

Additionally, the receiver 300 may request a trigger or a table from theserver by using MIME type. For example, the receiver 300 inserts MIMEtype into an Accept header of an HTTP request to specify trigger ortable request information. The server may represent information on atable or a trigger to be transmitted to the server by using acontent-type header of an HTTP response. For example, the header mayinclude the following message.

application/atsc2.0-ssc: information on a signaling channel (forexample, a signaling table)

application/atsc2.0-trigger: trigger information

Moreover, FIG. 118 is a view illustrating a timeline between a requestand a response during Short Polling when a trigger is transmittedthrough internet.

Referring to FIG. 118, when the content server operates in an HTTP ShortPolling mode, the receiver 300 may perform a trigger or table requestperiodically and may transmit a response message periodically.

When the content server operates in an HTTP Short Polling mode, theresponse message for the trigger or table request may start withPolling: Duration=<duration>. Here, <duration> may be in seconds indecimal form indicating a duration covered by a response message and maybe followed by a line feed character. The duration may be identical tothat requested to the receiver 300 and if there is no duration in therequest of the receiver 300, a default duration may be set by a contentserver and may be transmitted as a response.

Then, the response message may include a trigger or tables identified by<chan_id>. This trigger or tables may be scheduled to be transmittedduring a <duration> time interval from <start_time> through a broadcaststream. Then, triggers transmitted through internet may be arrangedaccording to the order in which the triggers are transmitted through abroadcast stream.

Then, after transmitting a response message, the server may terminateHTTP connection.

Moreover, when an event in HTTP response starts with Polling:Duration=<duration>, even if the HTTP connection is terminated by theserver, the receiver 300 does not attempt reconnection immediately andattempts connection again after a predetermined time in correspondenceto a time designated to the duration.

FIG. 119 is a view illustrating a timeline between a request and aresponse during HTTP Streaming when a trigger is transmitted throughinternet.

Referring to FIG. 119, when the receiver 300 requests an initial triggerstream, the server may transmit a trigger that is already transmitted atthat time and needs to be processed by the receiver 300 first through anHTTP streaming session. Then, the server may deliver newly generatedtriggers at the same time as a broadcast network through the HTTPstreaming session.

When the content server operates in an HTTP streaming mode, the responsemessage for the trigger or table request of the receiver 300 may startwith Streaming and may be followed by a line feed character.

If <start_time> requested to the content server is prior to a currenttime (a time at which the content server receives the request) of thecontent server, an initial response message may include a continuoustrigger set. This continuous trigger set may include all triggerstransmitted through a broadcast stream during a time interval from<start_time> to the current time of the content server among triggersfor a virtual channel identified by <chan_id>. Additionally, theresponse message may further include triggers transmitted through abroadcast stream according to the same request of the receiver 300.

Then, when the content server operates in a Streaming mode, it maymaintain HTTP connection to be opened while a new trigger istransmitted. The receiver 300 determines that connection is terminatedwhen a channel is selected and released.

Moreover, if <start_time> requested to the content server is equal to orlater than a current time (a time at which the content server receivesthe request) of the content server, an initial response message mayinclude triggers transmitted through a broadcast stream according to therequest of the receiver 300. Then, when the content server operates in aStreaming mode, it may maintain HTTP connection to be opened while a newtrigger is transmitted. The receiver 300 determines that connection isterminated when a channel is selected and released.

Moreover, when the server uses HTTP streaming for transmission, atrigger may be delivered in the following event format.

trigger event: this event may represent a trigger identical to a triggertransmitted through a broadcast channel. A data field of the event mayhave the following structure.

The data field may have the same value as the payload of packetcorresponding to a trigger transmitted through a broadcast channel andmay be encoded in a URL method.

The data field may be configured with a pair of key:value and may beconfigured with an unaligned combination separated by a comma. The keymay correspond to Timestamp and may represent a trigger time. The valuemay correspond to Trigger_data and may include a trigger parameterhaving the same format as a trigger transmitted through a broadcaststream. The data field may be transmitted in order with its valuesseparated by commas and no key designation.

pre-recorded-trigger event: this event may include a plurality oftriggers for content pre-recorded as one file. The receiver 300 mayignore or may not check another trigger event until the pre-recordedcontent is terminated. The data field structure may be configured with apair of key:value like the above-mentioned event and may be configuredwith an unaligned combination separated by a comma. The key maycorrespond to Triggrer_file_URL for locating pre-recorded content andthe value may correspond to a Reconnect-time that the receiver 300receives a new trigger.

Moreover, the content server may perform switching at any time betweenHTTP streaming and HTTP short polling. Accordingly, the following methodfor signaling for the receiver 300 may be used.

When the content server switches from Short Polling to Streaming, thecontent server may switch a mode by transmitting a Streaming responsemessage in correspondence to a continuous request of the receiver 300.

Then, when the content server switches from Streaming to Short Polling,the content server may terminate the HTTP connection with the receiver300 and then, may switch a mode by transmitting a Short Polling responsemessage in correspondence to a request starting from the receiver 300.

Moreover, FIG. 120 is a view illustrating a trigger structure accordingto another embodiment of the present invention.

Referring to FIG. 120, a trigger may include a version, a triggeridentifier, a trigger protocol version, a trigger target, a triggeraction, trigger data, and a trigger action time. Additionally, thetrigger may include a safe area flag and a plurality of coordinateinformation.

Additionally, as shown in FIG. 120, the trigger may include a safe areaflag and a plurality of coordinate information.

The safe area is an override area as compared to another area and thereceiver 300 displays a TDO, which is executed by a trigger having asafe area set, with the first priority so that the TDO is not covered byanother display area.

A safe area flag safe_area_flag may be a 1-bit field indicating whetheran override safe area is designated by the trigger.

A left x coordinate left_x_coord may be an 8-bit field indicating ahorizontal coordinate of the left lower corner in the override safearea.

A right x coordinate right_x_coord may be an 8-bit field indicating ahorizontal coordinate of the right upper corner in the override safearea and may have a right horizontal direction percentage value (aninteger between 0 and 100) on the basis of the left of a screen.

A left y coordinate left_y_coord may be an 8-bit field indicating avertical coordinate of the left lower corner in the override safe areaand may have an upper end vertical direction percentage value (aninteger between 0 and 100) on the basis of the lower end of a screen.

A right y coordinate right_y_coord may be an 8-bit field indicating avertical coordinate of the right upper corner in the override safe areaand may have an upper end vertical direction percentage value (aninteger between 0 and 100) on the basis of the lower end of a screen.

Moreover, FIG. 121 is a view illustrating a trigger stream descriptoraccording to an embodiment of the present invention.

The transmitter 200 or the server may transmit a trigger stream to thereceiver 300 and the trigger stream may be obtained from an elementarystream (ES) level descriptor loop of a program element and may betransmitted through internet. The transmitter 200 or the servertransmits a descriptor indicating information on such a trigger streamto the receiver 300, so that it may provide information through asignaling channel to allow the receiver 300 to receive a trigger streameasily.

As shown in FIG. 121, a trigger stream descriptor may include adescriptor tag, a descriptor length, a trigger stream identifier, atrigger stream profile, a target service count, and a target serviceidentifier.

The trigger stream identifier may include identification information foridentifying a trigger stream. For example, the receiver 300 may uniquelyidentify a trigger stream from a virtual channel of a PMT sectioncorresponding to the descriptor on the basis of a trigger streamidentifier.

The target service count may be an 8-bit unsigned integer indicating thenumber of NRT services including target content items of triggerstransmitted through a trigger stream in correspondence to acorresponding virtual channel.

The target service identifier may be an 8-bit unsigned integer foridentifying NRT services including target content items of triggerstransmitted through a trigger stream.

Additionally, the service manager 350 of the receiver 300 receives atrigger and delivers it to a TDO.

As described above, a state of a TDO may be shifted by a trigger and asynchronized service may be provided by a trigger at a time that abroadcasting company wants. In order for a TDO to provide such aservice, the TDO may be able to receive a delivered trigger. Asdescribed above, the service manager 350 of the receiver 300 may delivertrigger information to a target TDO according to the received trigger.Trigger information may be delivered to a TDO through an applicationprogramming interface (API).

An API delivering such trigger information to a TDO is described below.

For example, the service manager 350 of the receiver 300 may deliver aTDO to a trigger through an API designated by a TDO. Accordingly, theTDO may declare a trigger object for receiving a trigger in advance andmay receive a trigger through the declared trigger.

According to an embodiment of the present invention, the MIME type of atrigger object may be an application/atsc-trigger and in this case, theTDO may receive a trigger normally from the outside only when a triggerobject is declared in a specific page where the TDO is executed.

Moreover, according to an embodiment of the present invention, thetrigger object declared by the TDO may include a function interface forregistering the following event.

Event: function on TriggerReceived(Trigger trigger)

Then, the trigger class shown in the above event may include triggerinformation to be delivered to a TDO. The trigger information mayinclude properties below.

The properties may include at least one of readonlyTriggerProtocolVersion protocol_version, readonly Number trigger_id,readonly Number trigger_version, readonly TriggerTarget trigger_target,readonly Number trigger_action, readonly Number trigger_version, andreadonly Object data.

Moreover, each of TriggerProtocolVersion class and TriggerTarget classdeclared in the trigger class may have the following properties.

The TriggerProtocolVersion class may include readonly Numbermajor_version and readonly Number minor_version as its properties andthe TriggerTarget class may include readonly Number service_id andreadonly Number content_linkage as its properties.

The properties defined by such a trigger class may have the sameinformation as trigger data delivered through a broadcast network or aninternet network.

FIG. 122 is a view illustrating a usage example of a trigger and a TDOAPI according to an embodiment of the present invention.

As shown in FIG. 122, a trigger API used in a TDO may be implementedwith java script using HTML language.

As described above, a TDO may declare a trigger for receiving a triggeras a triggerObject and when a trigger is received, each of theabove-mentioned properties may be set and updated by performing afunction called on TriggerRecv.

FIG. 123 is a view illustrating a Trigger stream association descriptoraccording to another embodiment of the present invention.

As described above, according to an embodiment of the present invention,the receiver 300 may identify a trigger scream by receiving a triggerstream descriptor and may obtain metadata for a trigger stream from thetrigger stream descriptor. Additionally, the trigger stream descriptormay selectively include identification information on NRT servicerelating to a trigger stream.

Then, the NRT service relating to a trigger stream may mean NRT servicescorresponding to a trigger target TDO of triggers included in thetrigger stream. In order for the receiver 300 to easily recognize anassociation between a trigger stream and an NRT service, the transmitter200 may need to transmit such an association between a trigger streamand an NRT service to the receiver 300.

Accordingly, as shown in FIG. 123, the transmitter 200 may transmit atrigger stream association descriptor indicating an association to thereceiver 300.

For example, the transmitter 200 may include a trigger streamassociation descriptor in a descriptor loop of an SMT and then maytransmit it. The receiver 300 may determine that a trigger stream and anNRT service are associated on the basis of the NRT service correspondingto a descriptor loop where a trigger stream association descriptor islocated and trigger stream identification information included in thetrigger stream association descriptor.

As shown in FIG. 123, the trigger stream association descriptor mayinclude a descriptor tag field, a descriptor length field, a triggerstream count field, and a trigger stream identification field.

The trigger stream count field may be an 8-bit unsigned integerindicating the number of trigger streams determining TDOs in a specificNRT service of an SMT including the descriptor as trigger targets.

The trigger stream identification field may be an 8-bit unsigned integerindicating identification information on a trigger stream determiningTDOs in a specific NRT service of an SMT including the descriptor astrigger targets.

Accordingly, the receiver 300 may receive a trigger stream on the basisof the trigger stream identifier and may receive triggers from a triggerstream. Then, the receiver 300 may operate a TDO by processing receivedtriggers by using the above-mentioned API.

Besides that, the receiver 300 may identify a trigger stream throughvarious methods. For example, the receiver 300 may receive a triggerthrough an IP network. The receiver 300 may identify a stream forreceiving a trigger by obtaining a trigger URL from the above-mentionedInternet Location Table (ILT). Then, the receiver 300 may receive atrigger directly transmitted from a content server through an IPnetwork.

FIG. 124 is a view illustrating an ILT according to another embodimentof the present invention. FIG. 125 is a view illustrating a URL functioncode value table used in an ILT according to another embodiment of thepresent invention.

The ILT according to another embodiment of the present invention mayinclude address information through which the receiver 300 receives atrigger stream through internet.

For example, as shown in FIG. 124, the ILT according to anotherembodiment of the present invention may further include a trigger streamidentifier trigger_stream_id field in addition to the ILT shown in FIG.116. Then, URL_fuction_code corresponding to a trigger stream identifiermay be additionally allocated.

The fields described with reference to FIG. 124 are not described againand only additional fields are described as follows.

A URL function code URL_function_code field may represent the functionor purpose of a URL provided from the ILT and its detailed meaning isdescribed as follows with reference to FIG. 125.

When the URL function code value is 0, it may represent a URL for usagereporting and may be used for audience survey as described above.

When the URL function code value is 1, it may represent the URL of atrigger stream transmitted through internet according to anotherembodiment of the present invention.

The trigger stream identification trigger_stream_id field may be an8-bit field for identifying a trigger stream transmitted through a URLcorresponding to an internet location loop including this field.

In such a manner, the receiver 300 may receive an ILT according toanother embodiment of the present invention shown in FIG. 124 and mayobtain trigger stream identification information and address information(i.e., URL information) corresponding thereto from the received ILT.Then, the receiver 300 may access a server transmitting a trigger streamon the basis of the obtained trigger stream identification informationand address information and may obtain triggers from the receivedtrigger stream.

Moreover, according to another embodiment of the present invention, thereceiver 300 may receive signaling tables for an adjunct service of abroadcast stream in addition to a trigger through an IP network.

The signaling table for an adjunct service of a broadcast stream mayinclude at least one of an NRT-IT, an SMT, a TFT, an ILT, a PIT, and aPTCT, as described above. The receiver 300 may need to receive suchsignaling tables through internet. For example, if it is impossible forthe receiver 300 to receive a broadcast stream through a broadcastnetwork, signaling tables for an adjunct service for a currently viewingimage may need to be received through internet. Accordingly, thereceiver 300 may obtain broadcast information on a currently viewingimage through the above-mentioned various methods and, on the basis ofthis, may request signaling tables of an adjunct service from a serverand may receive them.

A request/response relationship of a signaling table through internetbetween the receiver 300 and a server according to an embodiment of thepresent invention is as follows.

A server signaling an adjunct service may transmit signaling tables fora specific virtual channel through HTTP. Accordingly, the receiver 300may transmit a signaling table request message in a full URL formatincluding a basic URL to a server. Especially, the signaling tablerequest message may include the basic URL of a server and extended queryinformation.

Accordingly, the receiver 300 may transmit a signaling table requestmessage of an adjunct service for a specific virtual channel by usingthe basic URL of a server and query information. For example, a requestmessage that the receiver 300 transmits may include virtual channelidentification information, start time information, durationinformation, update information, and signaling table information, and aquery for this may have the following format. Additionally, the querymay be located at the end of a full URL format of a request messagetransmitted to a server.

That is, the receiver 300 may transmit a signaling table request messagein a full URL format to a server through an internet network. Thesignaling table request message may include at least one queryinformation and the query information may be located at the end part ofa full URL format message. The query information may include first queryinformation and second query information. The first query information isas follows.

chan=<chan_id>&start=<start_time>[&duration=<duration>][&update]

chan_id may represent the channel number of a virtual channel and mayinclude a decimal notation of a major channel number and a minor channelnumber divided by a period.

start_time may represent a start time. The start time may be a serverside time reference relative time and may represent a start time of atime interval that the receiver 300 requests. For example, start_timemay be a millisecond unit time but the present invention is not limitedthereto.

The duration may represent a time interval. The duration may representthe length of a time interval requested from the receiver 300.

The update may be a boolean flag indicating whether a request of thereceiver 300 is for update. If there is no update information in therequest that the receiver 300 transmits, the request is an initialrequest transmitted from the receiver 300. If there is updateinformation in the request that the receiver 300 transmits, the requestmay be for update of a signaling table.

For example, the receiver 300 may designate first query informationduring request message transmission. The receiver 300 may designate acurrent time of a currently viewing image in start_time and maydesignate a time interval of tables to be received in the duration andmay mark whether to update in the update.

Especially, the receiver 300 may obtain a time of a broadcasting stationside transmitting a video frame of a currently viewing image and maydesignate the time as start_time.

Then, when a signaling server receives the request message and transmitsa response to the receiver 300 (i.e., transmitting signaling tables),the receiver 300 transmits the next request before a time interval endcovered by the response so that it may receive the next response beforethe time interval end. At this point, the receiver 300 may designate atime interval end time of a previous response to start_time and then maytransmit it. Accordingly, request and reply transmission may be providedwith a seamless interval.

FIGS. 126 and 127 are views illustrating a second query information andresponse relationship of a signaling table request message according toan embodiment of the present invention.

The signaling table request message that the receiver 300 transmitsthrough an internet network may be further extend by using additionalsecond query information.

The receiver 300 may include table information to be received in secondquery information as shown in FIG. 126 or 127. Such second queryinformation may be located at the end part after the first queryinformation of a signaling table request message transmitted to a serverin a full URL format.

For example, like &table=SMT, the receiver 300 may insert tableinformation to be received into a request message by designating aspecific table at the end part of a request message.

svc_id may represent the service identifier of an NRT servicetransmitted through a virtual channel in first query information and maybe expressed in a high order byte and low order byte of decimal notationseparated by a period.

Then, the second query information may selectively include squarebrackets ([ . . . ]). If there is no &svc list in the square brackets,the second query information may represent that the receiver 300requests signaling tables for all NRT services transmitted in acorresponding virtual channel. Only when requesting signaling tables fora specific NRT service, the receiver 300 may designate an NRT service byinserting a &svc list and svc_id in the square brackets.

Moreover, a Current NRT-IT and a Current TFT may represent a tableinstance existing within a time interval designated by the start time inthe first query information. Then, a Next NRT-IT and a Next TFT mayrepresent table instances of the next time interval after a timeinterval covered by the Current NRT-IT and the Current TFT. A FutureNRT-IT and a Future TFT may represent table instances to be transmittedthrough a broadcast stream after the next time interval.

Here, if the second query information includes an NRT-IT or a TFT, aserver receiving a request selectively transmits at least one of theNRT-IT or the TFT capable of covering a time interval designated to<start_time> and <duration> in the first query information so thatefficient table transmission may be performed.

Moreover, since overhead due to transmitting a table request one by onerepeatedly occurs, the receiver 300 may classify a plurality ofsignaling tables as a set and may request them at a time. Then,signaling tables for a plurality of adjunct services may be classifiedas a basic set, an extension set, and a full set.

The basic set may include at least one of an SMT, an NRT-IT, a TFT, andan ILT corresponding to NRT service transmitted to a specific virtualchannel by the first query information.

The extension set may include at least one of a PIT and a PTCTcorresponding to NRT service transmitted to a specific virtual channelby the first query information, besides the basic set.

The full set may further include a Future NRT-IT and a Future TFTbesides the extension set.

Each set classified in such a manner may be designated differentlyaccording to a broadcast server provider or an adjunct service providerand the present invention is not limited thereto. For example, a PSITset may represent TVCT, EIT, and ETT instances and a Basic NRT set mayinclude SMT, NRT-IT, and TFT instances corresponding to the serviceidentifier svc id of the virtual channel and an Extended NRT set mayrepresent PIT and PTCT instances besides the Basic set.

With a combination of such first query information and second queryinformation, the receiver 300 may request various conditions ofsignaling tables from a server. Additionally, the signaling tables mayinclude signaling tables for broadcast service itself in addition to anadjunct service of a broadcast service. For example, the signaling tablemay include a PSIP table for broadcast service.

Moreover, the server may transmit signaling tables in a response messagein response to the request of the receiver 300 e. Such a responsemessage may be transmitting through a polling method and is not limitedto a transmission method.

For example, the server may generate a response message of an HTTPmethod starting with Duration=<duration> and then may transmit it to thereceiver 300.

<duration> of a response message may be in minutes in decimal formindicating a time interval covered by a server response message and maybe followed by a newline character. The duration of the response messagemay be identical to that requested from the receiver 300 and if there isno duration designated in the request of the receiver 300, a defaultduration may be set by a signaling server.

Then, the response message may include signaling tables corresponding toa virtual channel identified by <chan_id>.

When receiving an initial request from the receiver 300, the server maytransmit signaling tables scheduled to take effect for a <duration> timeinterval from <start_time> and updated tables (e.g., a concatenated set)to the receiver 300. Then, the server may align signaling tablestransmitted through internet according to effective time order andtransmit them.

When receiving an update request from the receiver 300, the server maytransmit signaling tables scheduled to take effect for a <duration> timeinterval from <start_time> and updated tables (e.g., a concatenated set)to the receiver 300. In the same manner, the server may align signalingtables transmitted through internet according to effective time orderand transmit them.

Then, after transmitting a replay message, the server may terminate HTTPconnection.

Moreover, when an HTTP response starts with Duration=<duration>, even ifthe HTTP connection is terminated by the server, the receiver 300 doesnot attempt reconnection immediately and attempts connection again aftera predetermined time in correspondence to a time designated to theduration.

Table or table instances included in the response table may have thesame format as those transmitted through a broadcast stream. When tableor table instances include a plurality of sections, the sections may beincluded in a response message in a sequentially connected form.

A 32-bit unsigned integer indicating an update time of a signaling tablesection may be added to the front of each signaling table sectionincluded in the response message. For example, the 32-bit integer mayrepresent a service side reference time that the signaling table sectionis valid for the channel. The signaling table section cannot beduplicated and it is determined that a new version of a signaling tableis not duplicated.

Moreover, the receiver 300 that cannot receive broadcast stream directlymay obtain a signaling table through an ACR method. At this point, thereceiver 300 may receive virtual channel identification information oncurrently viewing content and a signaling server URL from a watermarkserver or a fingerprint server on the basis of part of a currentlyviewing AV content. The receiver 300 may receive various signalingtables relating to a virtual channel of the currently viewing content byaccessing a signaling server and may receive an adjunct service of thecurrently viewing content.

Then, the receiver 300 may receive a URL for receiving adjunct servicethrough various methods by accessing a signaling server. For example,the receiver 300 may obtain URLs for receiving adjunct service byreceiving the above-mentioned ILT.

For example, the receiver 300 may receive signaling tables including theILT by accessing a specific server URL obtained using ACR.

Then, the receiver 300 may obtain the URL address of an adjunct servicesignaling server corresponding to a currently viewing virtual channel byusing the ILT.

Then, the receiver 300 may receive adjunct service signaling tabletscorresponding to a currently viewing virtual channel by accessing theadjunct service signaling server.

Then, the receiver 300 obtains an SMT from an adjunct service signalingtable and may identify NRT services on the basis of the SMT.

Then, the receiver 300 may receive the identified NRT service on thebasis of the adjunct service signaling tables. Here, the receiver 300may receive adjunct service without tuning to another channel but abroadcasting station may not discover the receiver 300. Accordingly,information for allowing a broadcasting station to discover the receiver300 may need to be transmitted.

FIG. 128 is a view illustrating an ILT according to another embodimentof the present invention. FIG. 129 is a view illustrating aURL_fuction_code value table used in FIG. 128.

Referring to FIG. 128, the ILT according to another embodiment of thepresent invention may include a plurality of major channel number fieldsmajor_channel_number and minor channel number fieldsminor_channel_number corresponding to each URL_fuction_code besides theabove-mentioned embodiment of the ILT.

The meaning of URL_fuction_code used herein may be identical to thatshown in FIG. 129.

In more detail, when URL_fuction_code is 0, the URL of a loop includingURL_fuction_code field in the ILT may represent a URL for usagereporting for a virtual channel identified as the major channel numberand minor channel number fields.

Then, when URL_fuction_code is 2, the URL of a loop includingURL_fuction_code field in the ILT may represent a URL for receiving asignaling table for a virtual channel identified as the major channelnumber and minor channel number fields.

According to a configuration of the ILT depending on URL_fuction_code,the receiver 300 may perform usage reporting for a major channel numberand a minor channel number of a currently viewing channel. Accordingly,the above-mentioned issue that a broadcasting station does not discoverthe receiver 300 may be resolved.

Additionally, the receiver 300 may use various methods for abroadcasting station to discover the receiver 300 that does not receivebroadcast stream besides the above-mentioned ILT.

For example, a fingerprint server or a watermark server for ACR mayoperate as an NRT discovery server. Additionally, the fingerprint serveror the watermark server may signal access information on the NRTdiscovery server to the receiver 300. Additionally, the NRT discoveryserver may be operated by a provider of the receiver 300. The receiver300 may obtain access information on the NRT discovery server from areceiver provider server or may obtain access information on the NRTdiscovery server from a memory built in the receiver 300 itself.

Moreover, the receiver 300 may provide a TDO service according to anoperation of a TDO by a trigger. The transmitter 200 may transmit realtime data necessary for an operation of such a TDO. Accordingly, thereceiver 300 may provide a real time linked TDO service by receivingreal time data. For example, a TDO may provide real time stockinformation by using real time data. In such a manner, real time datafor a TDO may be transmitted to the receiver 300 via various paths.

The real time data for a TDO may be transmitted based on MPEG-2elementary stream (ES).

Additionally, the real time data may be included in a trigger and thentransmitted. A trigger including real time data in such a manner may bereferred to as a data type trigger.

The real time data for TDO may be transmitted through an IP basedbroadcast network or internet network, as mentioned above.

First, the real time data may be transmitted through FLUTE. Thetransmitter 200 may transmit real time data for a TDO by using an NRTservice transmitted through FLUTE. For this, the transmitter 200 mayallocate a specific consumption model with respect to the real time datafor a TDO. The consumption model, as described with reference to FIG.68, may be designated by a value of a consumption model field includedin an NRT service descriptor in a service level descriptor loop of anSMT. The receiver 300 may receive an NRT service corresponding to a datastream consumption model by a consumption model. The NRT servicecorresponding to a data stream consumption model may include real timedata for a TDO and also may include other data for an NRT service objectother than a TDO.

FIG. 130 is a view illustrating a consumption model field including adata stream consumption model according to an embodiment of the presentinvention. Descriptions of other fields are identical to those describedwith reference to FIG. 68.

Referring to FIG. 130, an NRT service where a value of a consumptionmodel field is designated to a data stream 0x05 may include at least onefile stream for a downloadable object or a declarative object (DO).Here, the meaning of the downloadable object or the declarative object(DO) may be used as including a Triggered Declarative Object (TDO) or ageneral NRT service object. A TDO may be one of objects operating in aDO execution environment. An NRT service where a consumption model isdesignated to data stream may be received only when a DO operating inthe receiver 300 requests download and delivery through an API providedas part of an execution environment and a file stream included in thereceived data stream service may be delivered to only the DO.

FIG. 131 is a flowchart illustrating a method of a receiver providingdata for a DO to receive broadcast service by receiving an NRT serviceallocated to a data stream consumption model.

Referring to FIG. 131, first, the receiver 300 obtains an SMT fromservice signaling data in operation S9200. The receiver 300 may receiveservice signaling data by accessing a broadcast service channel and mayobtain an SMT from the service signaling data.

Then, the receiver 300 parses an NRT service information descriptor fromthe SMT in operation S9205.

Here, the receiver 300 identifies an NRT service corresponding to thedata stream consumption model among the identified NRT services inoperation S9210.

When the reception of the data stream consumption model is selected, thereceiver 300 obtains content item information configuring the NRTservice identified as a data stream consumption model from an NRT-IT inoperation S9215.

Then, the receiver 300 receives files configuring a content item on thebasis of an SMT and an NRT-IT in operation S9220.

Then, the service manager 350 of the receiver 300 provides real timedata for DO to a DO by using the received files in operation S9225.

Then, once the download is completed, the service manager 350 of thereceiver 300 may deliver a file to a DO.

Hereinafter, a method of transmitting files configuring adjunct servicethrough an internet network is described.

The adjunct service, for example, files configuring ATSC 2.0 content,may be transmitted through an internet link by using an HTTP or HTTPSprotocol. Which one of HTTP or HTTPS protocol the transmitter 200 usesis determined based on whether a content item transmitted throughinternet is updated (signaled by an update_available field of an entrycontent item in an NRT-IT) or how large the file is. In the descriptionbelow, HTTP/S may mean HTTP or HTTPS.

When a content item is not to be updated (when an update_available fieldis 0), the transmitter 200 and the receiver 300 may transmit a requestand response through a general HTTP/S protocol.

When a content item is to be updated (when an update_available field is1), the transmitter 200 and the receiver 300 may transmit files of lessthan a specific size through an HTTP/S streaming method and may transmita request and response through a general HTTP/S protocol in the case offiles of more than a specific size. Then, the transmitter 200 may notifythe receiver 300 that update is transmitted as HTTP/S streaming througha typical HTTP/S.

Here, in order to minimize simultaneous HTTP accesses to one server of aplurality of receivers 300, a multi-file HTTP streaming protocol methodmay be used. According to an embodiment of the present invention, aplurality of file HTTP streaming requests and responses are described

FIG. 132 is a view illustrating an XML format of a multi-file HTTPstreaming request message according to an embodiment of the presentinvention.

Referring to FIG. 132, the multi-file HTTP streaming request may includeURL list information o initial files that the receiver 300 is toreceive. Additionally, the multi-file HTTP streaming request may furtherinclude update URL information on each file.

Additionally, although not shown in FIG. 132, the multi-file HTTPstreaming request that the receiver 300 transmits may includeidentification information specifying a content item or NRT service.Additionally, like XML shown in FIG. 132, the multi-file HTTP streamingrequest may further include a list of content items to be receivedinitially, a list of content items to be updated, or various ATSC 2.0service list information.

Then, the receiver 300 may designate a content item in the multi-fileHTTP streaming request and may designate only specific files in thecontent item as sub elements and then, may transmit them to a server. Inthis case, the content item may have a Base URL attribute and mayrepresent the base URL of the URLs of files included as sub elements.Accordingly, when a URL corresponding to each file included in a requestmessage has a relative path format, a server may determine that each URLis a relative path URL on the basis of the basic URL of the contentitem. However, another file may have an absolute path and in this case,a server may determine the URL as an absolute path without applying thebasic URL.

Moreover, when transmitting a new file, the transmitter 200 or theserver may immediately transmit a file to be updated or files newlyadded to a content item to the receiver 300 opening a multi-file HTTPstreaming session without an operation of notifying the receiver 300whether to update the file or add a new file.

For example, when a newly added file appears in the multi-file HTTPstreaming session, the receiver 300 may determine which content item ofwhich NRT service a file relates to through a header added to this file.Then, the receiver 300 may perform a processing operation of deliveringa newly added file to NRT service or a DO.

Moreover, the multi-file HTTP streaming response message may have amulti part MIME message format. Each part may include a messageindicating whether a file corresponding to a response message is a fileof less than a specific size, a file of greater than a specific size, orupdatable.

Additionally, an initial part of a response message may include files ofless than a specific size in an initial file list and a notificationmessage on whether files of greater than a specific size in an initialfile list are updated. (The initial parts of the message shall containall the small files in the InitialFiles list, and notifications ofupdates available for all the large files in the InitialFiles list.)

Then, each of parts following the initial part may include updates offiles of less than a specific size occurring after receiving a requestmessage and an update notification message of files of larger than aspecific size occurring after receiving a request message.

Additionally, the header of each part in an MIME message may include aContent-Location header field and the Content-Location header field mayinclude URL information on a file corresponding to the part.

Moreover, the MIME message including a file update notification messagemay include only a part header and may include an empty body. The partheader may include a Content-Location header field.

Then, when receiving an HTTP/S request including the URL for a file tobe updated and not including a multi-file request XML message in thebody from the receiver 300, the server may return a file identified bythe URL to the receiver 300.

First, the receiver 300 may receive a file from a specific serverthrough HTTP/S streaming and then may identify files to be updated.

Then, the receiver 300 may perform a multi-file HTTP/S streaming requestincluding an InitialFiles element including the URL of files to bereceived. The multi-file HTTP/S streaming request may exclude aFileUpdates element.

Then, the receiver 300 may obtain MIME message parts from a responsemessage. The receiver 300 may extract files of less than a specific sizefrom a response message and may perform a typical HTTP/S request forobtaining files identified by notifications.

After a predetermined time or when deletion of a file list is necessary,the receiver 300 may perform a new multi-file http/s streaming request.The new multi-file http/s stream request may include an InitialFileslist or the URLs of new files in a FileUpdates list. In order to preventmissing when a file is changed by update, the receiver 300 may terminatea connection for an existing request while transmitting a new request.

When HTTP/S streaming is disconnected, the receiver 300 may transmit anew HTTP/S streaming request. If there are important files set not tomiss update (for example, when the receiver 300 should contain thelatest version of a file), the receiver 300 may include the URLs of thefiles in an InitialFile list of a new HTTP/S streaming request. Thereceiver 300 may include the URLs of other files in a FileUpdates listof a new HTTP/S streaming request.

Moreover, real time data for the above-described TDO may be transmittedthrough such HTTP/S streaming. The transmitter 200 may transmit realtime data as continuously updated content item.

Accordingly, the transmitter 300 may set an updates_available fieldvalue of an NRT-IT corresponding to a real time data content item for aTDO to 1 and may transmit files configuring the real time data contentitem for a TDO through the above-described multi-file HTTP/S streamingmethod.

FIG. 133 is a view illustrating an ILT syntax according to anotherembodiment of the present invention. FIG. 134 is a table illustrating aURL function code used in the ILT shown in FIG. 133.

Referring to FIG. 133, the URL of a server transmitting a file throughmulti-file HTTP/S streaming may be included in an internet locationtable and then transmitted from a signaling server to the receiver 300.

For this, as shown in FIG. 134, 3 may be newly defined as a value ofURL_function_code. First, since descriptions that a value of a URLfunction code is 0, 1, or 2 are identical to those relating to FIG. 129,overlapping descriptions are omitted.

Then, when a value of the URL function code is 3, a URL_byte fieldcorresponding to the URL function code value may represent the URL of aserver receiving files transmitted through a virtual channel identifiedby a major channel number and a minor channel number and updatenotification of the files.

Accordingly, when receiving an ILT from a signaling server, the receiver300 may parse URL function code and URL_byte from the ILT. Then, thereceiver 300 may determine the purpose of URL information obtained fromURL_byte according to a URL function code. For example, when a value ofthe URL function code is 3 according to an embodiment of the presentinvention, the receiver 300 may identify a virtual channel by using amajor channel number and a minor channel number corresponding to the URLfunction code and may access a server receiving files transmittedthrough a virtual channel identified by using URL information obtainedfrom URL_byte and update notification of the files.

Moreover, a TDO operated by the receiver 300, as described above, mayreceive real time data additionally. For example, in the case of a TDOproviding stock quotes, the TDO may obtain real time stock informationreceived by the receiver 300 and then may display it to a user.

According to an embodiment of the present invention, the receiver 300may receive real time data that a TDO is to obtain through a DocumentObject Model (DOM) API.

FIG. 135 is a view illustrating an XML format of a trigger API receivingreal time data for a TDO according to an embodiment of the presentinvention.

For example, a TDO may generate a RealTimeData Object for receiving realtime data. The service manager 350 of the receiver 300 may generate anobject by declaring a real time data object for a TDO. Then, the servicemanager 350 may control a TDO so that the TDO receives real time data byusing the generated real time data object.

Then, according to an embodiment of the present invention, the MIME typeof a real time data object may be designated asapplication/atsc-realtimedata. The service manager 350 may generate areal time data object to correspond to a page where a TDO is executedand may deliver real time data received from the outside to the realtime data object.

Additionally, according to an embodiment of the present invention, thereceiver 300 may control the generated real time data object by using anevent and a method below.

Event: function onRealTimeFileReceived(RealTimeFile rtdata)

Method: function registerRealTimeData(String service_id, Booleanurl_flag), function registerRealTimeFile(String content_location,url_flag)

As mentioned above, the method may include a registerRealTimeDatafunction and a registerRalTimeFile function.

The registerRealTimeData function may be a function for registering realtime data in an NRT service identified by service id and receiving them.

The registerRalTimeFile function may be a function for registering eachfile of real time data and receiving them.

url_flag may represent a data format that the receiver 300 delivers to aTDO when real time files are received. For example, the URL flag mayrepresent whether a data format to be delivered is a url format or acontent itself format.

Then, an on RealTimeFileReceived event may perform a function fornotifying a TDO each time real time data files registered by theabove-mentioned registration functions are received.

Then, a RealTimeFile class defined as a real time file in a TDO mayinclude information on individual files for real time data delivered tothe TDO. Then, each of the classes may include a property below.

The property may include at least one of readonly Stringcontent_location, readonly String content_type, readonly Stringcontent_encoding, and readonly String file_content.

Here, when url_flag of the above-described real time file registrationfunctions is set to true, the registered real time file may includecontent_location, content_type, and content_encoding properties. Then,when url_flag is set to false, the registered real time file may includecontent_encoding and file_content properties.

Moreover, another embodiment of a signaling table transmitted throughinternet is described below.

Signaling tables transmitted through internet may include a broadcastservice signaling table and an NRT service signaling table. Thesignaling tables may be PISP tables including a TVCT, an EIT, and anETT, for example, and may be NRT tables including an SMT, an NRT-IT, aTFT, an ILT, a PIT, and a PTCT.

When the receiver 300 receives only an uncompressed audio and video, thesignaling tables may not be received from a broadcast signal and may bereceived through an internet network. Additionally, in the case that thereceiver 300 receives a full broadcast signal, when signaling tables arereceived through an internet network, without adjusting a tuner orwaiting for table reception, since a program and a service guide aredisplayed on a screen area for a user, an efficient program and serviceguide may be provided.

Such a signaling table transmission through an internet network may beperformed between the receiver 300 and a signaling server through arequest/response method of an HTTP protocol.

Then, the request message, as mentioned above, may be transmitted in afull URL format including first query information and second queryinformation and according to another embodiment of the presentinvention, the first query information may have the following format.

start=<start_time>[&timebase=<timebase>][&duration=<duration>][&update]

The base URL included in a request message may correspond to a specificbroadcast stream. For example, when the receiver 300 cannot access afull broadcast stream and receives only some uncompressed AV images, thebase URL may be received through an internet network by using theabove-described ACR method.

Then, the receiver 300 may transmit a signaling table request messageincluding the base URL to a signaling server and may obtain a signalingtable from a response of a server. Moreover, the receiver 300 accessibleto a broadcast stream may obtain the base URL from an ILT in thebroadcast stream.

Then, the transmitter 200 may include a URL for obtaining PSIP and NRTsignaling tables of a specific physical channel in addition to aspecific virtual channel in an ILT and then may transmit it. In thiscase, a physical channel may be identified through a major channelnumber. Additionally, the receiver 300 may identify a virtual channellist from a VCT and may receive signaling tables for a specific adjunctservice additionally through an internet network. Then, the receiver 300may receive all signaling tables in a specific physical channel throughan internet network.

According to an embodiment of the present invention, the first queryinformation may include <start_time> and start_time may represent astart point of a time interval requesting a signaling table. Here,start_time may be the UTC time and may be a time stamp received from anACR server. For example, start_time may determined whether there is<timebase> in the first query information. If there is no Timebase,start_time may represent a UTC time and if there is a timebase,start_time may represent a time stamp obtained from an ACR server or arelative time with respect to a reference time.

FIG. 136 is a view illustrating a second query information tableaccording to another embodiment of the present invention.

Referring to FIG. 136, the query information according to anotherembodiment of the present invention may further include information forspecifying a Basic PSIP, a VCT, an EIT, and an ETT in addition to thesame portions in the table described with reference to FIGS. 126 and127.

Here, the Basic PSIP set may represent VCT, EITs, and ETTs and may meana signaling table for virtual channels in a physical channel.

Then, if there is chan_id in the second query information, chan_id mayrepresent a specific virtual channel corresponding to a table requestand may include a major channel number and a minor channel number. Ifthere is no Chan_id, the second query information may represent arequest for tables for all virtual channels transmitted throughbroadcast stream.

Moreover, if there is ETM_id in the second query information, ETM_id mayrepresent a specific ETT instance that the receiver 300 is to request.The ETT instance may be the same as that defined in the ATSC PSIPstandard. If there is no ETM_id, it may represent that the requestmessage is not for the purpose of all ETT instances.

Moreover, if there is svc_id in the second query information, asdescribed above, svc_id may represent a service identifier of a specificNRT service in a broadcast stream that the receiver 300 is to request.If there is no svc_id, it may represent that the request message is notfor the purpose of NRT service.

Moreover, as a response to a request message, a signalling server maytransmit a response message including signalling tables to the receiver300.

According to an embodiment of the present invention, the responsemessage may include a diffusion parameter. The receiver 300 may requesta signalling table again just before a time interval designated byDuration ends. At this point, if a plurality of receivers requestsimultaneously, it may cause the load of a server.

According to an embodiment of the present invention, the server mayinclude a diffusion parameter in a response message and then maytransmit it.

The receiver 300 may determine the next signalling table request time onthe basis of the diffusion parameter.

Such a diffusion parameter may be included in the header of an HTTPresponse. Additionally, the diffusion parameter may be included in thebody of an HTTP response. If the diffusion parameter is found in theresponse message, the receiver 300 may transmit the next signallingtable request at a random time in a time interval based on the parametervalue.

Moreover, the receiver 300 may provide Electronic Program Guide (EPG)including guide information on broadcast service by using NRT service.Moreover, the receiver 300 may provide EPG on the basis of an Eventinformation table (EIT) of a PSIP table like an existing receiver, andmay additionally provide EPG provided through NRT service, if necessary.When EPG is provided using NRT service, the receiver 300 receivesimages, videos, or executable contents in advance through a servicesignaling channel or an internet network, and provides the received EPGservice according to a user's request.

Moreover, according to an embodiment, the transmitter 200 may furtherinclude information for providing NRT service guide in a VCT or an EITand then, may transmit it. Such information may be included in aspecific descriptor, and may express a descriptor for providing NRTservice guide as an adjunct EPG descriptor. The receiver 300 parses theEPG descriptor from a descriptor loop of a VCT or an EIT and displaysEPG on NRT service.

Such an adjunct EPG descriptor may include various information toprovide NRT service guide. For example, the adjunct EPG descriptor mayinclude information on whether there is an adjunct NRT service added toa specific virtual channel or event A/V stream and transmitted andwhether an existing adjunct NRT service is accessed according to acontrol. Moreover, the adjunct EPG descriptor may include information onwhether a list of NRT service included in an NRT virtual channel andeach NRT service are accessed according to a control.

Moreover, the adjunct EPG descriptor, as mentioned above, may beincluded in a channel level descriptor loop of a VCT (a TVCT or a CVCT),and may be included in an event level descriptor loop of an EIT.Accordingly, the receiver 300 may display EPG on data service or NRTservice by using a PSIP table transmitted through a broadcast channel oran internet network, without extracting complex data or other tablesthrough each virtual channel or signaling channel.

The adjunct EPG descriptor may include capability information on NRTservice. The capability information may include information on thecapability of the receiver 300 with which an NRT service included in acorresponding virtual channel or event is successfully played.Therefore, the receiver 300 may not display the existence of acorresponding NRT service in the EPG of the NRT service if a requiredcapability is not provided on the basis of the capability information.Then, the capability information may be included in an NRT Capabilitiesdescriptor, and also is included in a VCT or an EIT in addition to theadjunct EPG descriptor, and then transmitted.

FIG. 137 is a view illustrating a syntax of an adjunct EPG descriptoraccording to an embodiment of the present invention.

Referring to FIG. 137, the adjunct EPG descriptor may include adescriptor tag field, a descriptor length field, a num_of_NRT_servicesfield, and at least one NRT service loop divided by a for loop. The atleast one NRT service loop may include a service_id_ref field, aconsumption model field, an access_controlled field, ashort_service_name_length field, and a short_service_name field.

FIG. 138 is a view illustrating a syntax of an adjunct EPG descriptoraccording to another embodiment of the present invention.

Referring to FIG. 138, the adjunct EPG descriptor according to anotherembodiment of the present invention may be referred to asservice_enhancements_descriptor. A service enhancements descriptor mayinclude capability information of the receiver 300 to use each NRTservice. Accordingly, the service enhancements descriptor furtherincludes capability code information necessary for using each NRTservice, and unlike FIG. 85, may further include at least one ofcapability string and capability set to represent capability informationthat is required by the receiver 300 to launch or play NRT service.

Moreover, the receiver 300 may provide Electronic Program Guide (EPG)including guide information on broadcast service by using NRT service.Moreover, the receiver 300 may provide EPG on the basis of an Eventinformation table (EIT) of a PSIP table like an existing receiver, andmay additionally provide EPG provided through NRT service, if necessary.When EPG is provided using NRT service, the receiver 300 receivesimages, videos, or executable contents in advance through a servicesignaling channel or an internet network, and provides the received EPGservice according to a user's request.

According to an embodiment of the present invention, the transmitter 200allocates an additional consumption model corresponding to EPG in orderto transmit such an extended EPG through NRT service, and the receiver300 provides EPG service by performing a predetermined operation when itis determined as EPG according to a consumption model.

FIG. 139 is a view illustrating a meaning according to each value of aconsumption_model field in an NRT service descriptor when an EPGconsumption model is allocated according to an embodiment of the presentinvention.

As described with reference to FIG. 53, the consumption_model field isincluded in NRT_service_descriptor and is a field indicating whichmethod for consumption_model NRT service that NRT_service_descriptorrepresents uses. According to an embodiment, the consumption_model fieldmay represent an EPG consumption model. A field value for EPGconsumption model may be 0x05.

NRT service allocated as an EPG consumption model may include at leastone content item. Such content items may include information on abroadcasting service that is currently in service. For example, eachcontent item may include virtual channel service information accordingto a broadcast channel, TV event information, NRT service information,or information on content items of NRT service. Also, each informationis collected in an html page format and is provided in an EPG formatthrough the receiver 300.

Also, the receiver 300 connects broadcast information provided in EPGwith other NRT service objects or various multimedia contents. For this,the transmitter 200 inserts a link descriptor or an event descriptor forreceiving contents connected to broadcast information into SMT or NRT-ITand transmits it. Additionally, the transmitter 200 inserts a linkdescriptor or an event descriptor including the above broadcastinformation into a VCT or an EIT and transmits it.

Also, the transmitter 200 generates a linkage descriptor correspondingto an NRT service allocated as an EPG consumption model, and inserts itinto at least one of a VCT, an EIT, an SMT, and an NRT-IT to correspondto each service or channel, and transmits it. A transmission method ofthe transmitter 200 by using a linkage descriptor or a reception andservice providing method of the receiver 300 will be described later.

An NRT service designated as an EPG consumption model may includeextended EPG information for EPG on a program or service that thereceiver 300 provides. Since the extended EPG information may includerich and diverse multimedia data, the receiver 300 provides to a user aguide to a program or service through rich and various methods.

At least one content item included in an NRT service designated as anEPG consumption model may corresponding to one virtual channel, oneevent, or one NRT service, and may include related information on eachcorresponding virtual channel, event, or NRT service. The receiver 300may obtain such related information on the basis of a linkagedescriptor.

For example, when a user's additional information request on a specificvirtual channel, event, or NRT service displayed on a program or serviceguide is provided, its service may be provided by using a content itemof an EPG consumption model NRT service linked with the additionalinformation requested specific virtual channel, event, or NRT service. Acontent item of an NRT service of an EPG consumption model may includeat least one of preview, related HTML page collection, a movie posterimage.

Accordingly, when there is a user's additional request on a specificevent in the displayed service guide, the receiver 300 launches apreview content item of an NRT service of an EPG consumption modelcorresponding to an additional request target, and displays it to auser, so that extended EPG service is provided.

Moreover, an NRT service (or, an EPG NRT service) designated as an EPGconsumption model may be downloaded in the background so that a user maynot recognize it. Also, content items of an EPG NRT service downloadedthrough the background may be presented in the receiver 300 when thereis a user's request on the displayed broadcast service guide.

Furthermore, when content items of EPG NRT service are downloaded andstored through the background, the service manager 350 of the receiver300 updates the received and stored EPG NRT service when it isdetermined that there is an updated version after periodicallyconfirming and monitoring the content items.

Then, among the downloaded and stored content items of EPG NRT service,a content item linked with a specific virtual channel, specific event,or NRT service whose additional information is requested by a user maybe launched or presented in a broadcast program or service guide thatthe receiver 300 provides. For this, the receiver 300 may display that acontent item of an EPG NRT service including additional informationcorresponding to each virtual channel, event, or NRT service is receivedor stored. The receiver 300 may display an indicator displaying theabove in a service guide.

Also, the receiver 300 or the service manager 350 of the receiver 300may close or exit the launched or presented content items of EPG NRTservice when a user selects a virtual channel, an event, or NRT servicedifferent from the above-mentioned specific virtual channel, event, orNRT service from a broadcast program or service guide. Also, even when auser selects a close command from a broadcast program or service guide,the receiver 300 may close or exit the launched or presented contentitem of EPG NRT service.

FIG. 140 is a flowchart illustrating a method of providing EPG on thebasis of an NRT service of an EPG consumption model, as a method ofreceiving broadcasting service according to an embodiment of the presentinvention.

Referring to FIG. 140, the receiver 300 first receives a VCT, an EIT, anSMT, and an NRT-IT in operation S9001 and parses a service leveldescriptor of SMT in operation S9003.

The receiver 300 may receive an SMT through a service signaling channelby using the service manager 350, and may parse a plurality of loopscorresponding to each NRT service from the received SMT. The parsed eachloop may be referred to as a service level descriptor. Then, thereceiver 300 may parse service level descriptors including an NRTservice descriptor from each service level descriptor loop. An NRTservice descriptor may include detail information on an NRT servicecorresponding thereto. Also, the detail information may includerequirement information of a receiver to provide a corresponding NRTservice. Accordingly, the receiver 300 determines whether the receiver300 is capable of providing NRT service on the basis of an NRT servicedescriptor.

Accordingly, the service manager 350 of the receiver 300 parses a PSIPtable from a broadcast signal transmitted through a broadcast channeland parses a VCT and an EIT from the parsed PSIP table. The receiver mayparse a VCT and an EIT by using a PSIP handler.

Then, the receiver 300 analyzes the parsed service level descriptor inoperation S9005, confirms NRT_service_descriptor, and determines whethera value of the consumption_model field in NRT_service_descriptorrepresents an EPG consumption model. The receiver 300 determines this byreferring to the table of FIG. 74. Then, if the value does not representan EPG consumption model, the receiver 300 performs an operationaccording to the above-mentioned another NRT service consumption model.

However, if the value represents an EPG consumption model, the receiver300 determines that an NRT service designated as the EPG consumptionmodel is transmitted. In this case, the receiver 300 obtains receptioninformation of an NRT service of the EPG consumption model in operationS9007.

The reception information of an NRT service of an EPG consumption modelmay include the service id of the NRT service and the content linkage ofcontent items. As mentioned above, the service id may be included in anSMT and the linkage information between content items may be included inan NRT-IT. Accordingly, the receiver 300 obtains NRT service receptioninformation of an EPG consumption model on the basis of the SMT and theNRT-IT.

Then, the receiver 300 accesses a FLUTE session on the basis of theobtained reception information and receives and stores the content itemsconfiguring the obtained NRT service of the EPG consumption model inoperation S9009. The reception of an NRT service of an EPG consumptionmodel may be made in the background without a user's recognition.Accordingly, the NRT service of an EPG consumption model may becontinuously received regardless of a user's selection. However, thereception method may be changed according to a user's setting. Forexample, the receiver 300 may not receive the NRT service of an EPGconsumption model according to a user's setting, receives it in theforeground, or receives it according to a user's set period.Accordingly, the receiver 300 receives an EPG service extended accordingto a user's preference, and provides it.

Additionally, the receiver 300 receives and manages an NRT service of anEPG consumption model in a storage unit through the service manager 350.However, as mentioned above, in order to receive and manage an NRTservice of an EPG consumption model in a storage unit, a constantpredetermined size of storage space may be required. Additionally, theallocated amount of such a storage space may be transmitted through thetransmitter 200 according to a service provider's intention. Therefore,according to an embodiment of the present invention, the receiver 300allocates a predetermined area of a storage unit of the receiver 300 asa storage area of an NRT service of an EPG consumption model, receivesEPG service in an allocated area, and then stores and manages it.Accordingly, the transmitter 200 includes information on the storagearea in an NRT service descriptor and then, transmits it to the receiver300. In this case, the receiver 300 may receive, store, and manage EPGservice in a designated area.

Moreover, a content item of an NRT service designated as an EPGconsumption model may be transmitted through IP in addition to abroadcast service channel. The transmission through IP may be performedthrough the NRT service transmitting method through an internet network.For example, the receiver 300 obtains URL information to receive acontent item of an NRT service designated as an EPG consumption model onthe basis of an NRT-IT, and receives files configuring a content itemthrough an internet network on the basis of the obtained URLinformation. Accordingly, the receiver 300 receives content item filesin an NRT service of an EPG consumption model, which are transmittedthrough an internet network, through IP, and stores it.

Then, the receiver 300 provides a service guide on the basis of theparsed VCT and EIT in operation S9011.

Once the guide is provided, a user may select a desired content, forexample, a specific virtual channel, a specific program (event) or aspecific NRT service, from the displayed EPG. Accordingly, the receiver300 selects a corresponding content (a virtual channel, event, or NRTservice object) according to a user's selection in operation S0913. Auser may display a list of desired information contents in highlight,position an interface point on a content list, or select a content byusing a gesture.

Then, the receiver 300 first provides a service guide on the basis ofthe parsed VCT and EIT. Then, the receiver 300 determines whether thereis an additional information request on the selected content inoperation S9015. If there is no additional information request,operation S9011 is continuously performed.

Here, a receiver may display an indicator indicating the request aroundan additional information available content list by using the servicemanager 350. Additionally, the receiver 300 may lead a user to requestadditional information on a content having an indicator displayedthereon. The indicator may be displayed when an NRT service of the EPGconsumption model is received completely. The additionally information,for example, may include preview information (image information or imageinformation) included in a content item of an NRT service of an EPGconsumption model or related home page information.

Moreover, when there is an additional information request on theselected content, the receiver 300 identifies a content item of an NRTservice of an EPG consumption model corresponding to the selectedcontent in operation S9017.

The receiver 300 identifies content items corresponding to the selectedcontent from the received and stored NRT service of the EPG consumptionmodel by using the service manager 350. For example, when the selectedcontent is a specific virtual channel, the receiver 300 obtains contentitem identification information of an NRT service designated as an EPGconsumption model from the linkage information corresponding to aspecific virtual channel included in VCT and then, based on this,identifies a content item corresponding to a specific virtual channelfrom the content items of the received EPG consumption model NRTservice.

Moreover, when the selected content is a specific program (event), thereceiver 300 obtains content item identification information of an NRTservice designated as an EPG consumption model from the linkageinformation corresponding to a specific event or program included in EITand then, based on this, identifies a content item corresponding to aspecific program (event) from the content items of the received EPGconsumption model NRT service.

Then, when the selected content is a specific NRT object, the receiver300 obtains content item identification information of an NRT servicedesignated as an EPG consumption model from the linkage informationcorresponding to a specific event or program included in SMT or NRT-ITand then, based on this, identifies a content item corresponding to aspecific service object from the content items of the received EPGconsumption model NRT service.

Then, the receiver 300 provides additional information on the selectedcontent on the basis of the identified content item in operation S9019.

The receiver 300 may provide additional information on the selectedcontent by launching or presenting the identified content item. Theadditional information, as mentioned above, may include various and richmultimedia information to provide extended EPG. Accordingly, a user mayrequest additional information while watching a service guide, and mayobtain various and rich EPG information on the selected content at therequest.

FIG. 141 is a view illustrating a linkage between EPG and each tableaccording to an embodiment of the present invention.

Referring to FIG. 141, the EPG 400 may include an NRT service guide 401and a broadcast program guide 402. The receiver 300 may analyze a VCTand an EIT to generate the NRT service guide 401 or the broadcastprogram guide 402 and display it.

Moreover, the receiver 300 may obtain information on a content item ofan NRT service of an EPG consumption model corresponding to each NRTservice, virtual channel, or event on the basis of an SMT, a VCT, or anEIT, and may provide additional information by using a content item ofan EPG service corresponding to the NRT service, virtual channel, orevent that a user selects.

Furthermore, when there is an additional information request on avirtual channel 3-2, the receiver 300 may obtain EPG content itemidentification information on the virtual channel CH 302 correspondingthereto through linkage information in a VCT. Then, the receiver 300 mayidentify a corresponding content item item3 from NRT-IT corresponding toan NRT service of an EPG consumption model to launch or present it sothat additional information on EPG using NRT service may be provided.

In the same manner, when there is an additional information request onan event E321, the receiver 300 may obtain EPG content itemidentification information on a virtual channel CH 302 correspondingthereto through linkage information in an EIT. Then, the receiver 300may identify a corresponding content item iteml from an NRT-ITcorresponding to an NRT service of an EPG consumption model to launch orpresent it so that additional information on EPG using NRT service maybe provided.

FIG. 142 is a view illustrating an EPG provided according to anembodiment of the present invention.

As shown in FIG. 142, the EPG 400 may include a highlighter 403 forindicating a content that a user selects and an indicator 404 forindicating available additional information in addition to the NRTservice guide 401 and the broadcast program guide 402.

A user may select a specific content, for example, a specific NRTservice, a specific virtual channel, or a specific broadcast program(event) through the highlighter 403.

Then, the receiver 300 may determine whether an NRT service of an EPGconsumption model is received in correspondence to each NRT service,virtual channel, or event, and may display the indicator 404 indicatingthat additional information is available. Here, the indicator 404 may bedisplayed around a corresponding content list. Additionally, thereceiver 300 may display the indicator 404 on a content that a userselects according to a setting, and also may display the indicator 404on a content that a user does not select. In FIG. 142, although theindicator 404 is displayed in a circular form, it is not limitedthereto, and thus may be displayed in at least one form of characters,symbols, or figures, which represent that additional information oncontent is available.

FIGS. 143 and 144 are views illustrating an EPG screen when a userrequests additional information according to an embodiment of thepresent invention.

As shown in FIG. 143, according to an embodiment, when a u ser selectsthe indicator 404 to request additional information on a specificcontent, an extended EPG is displayed by the launched or presentedcontent item of an EPG consumption model NRT service. For example, asshown in FIG. 143, the receiver 300 may further display an extendedguide 405 corresponding to a content that a user selects. The extendedguide 405 may include a menu for selecting at least one of previewinformation, related home page information, detailed information on acorresponding content, and poster information.

Then, when a user selects a specific menu, for example, previewinformation, as shown in FIG. 79, a preview information screen 406 on acorresponding content may be additionally displayed on the EPG. Thepreview information screen 406 may represent preview informationincluded in a content item of an EPG consumption model NRT service asshown in FIG. 144. The preview information, as shown in FIG. 79, mayinclude detail content, video, or VOD information on the correspondingcontent E321, and may be played according to a user's selection.

FIG. 145 is a view illustrating linkage information linked with othertables according to another embodiment of the present invention.

As shown in FIG. 145, linkage information may be included in a linkagedescriptor, and also may be included in a descriptor loop correspondingto a content item of a specific channel, specific event, specific NRTservice, or a content item of a specific NRT service of each table of aVCT, an EIT, an SMT, or an NRT-IT, and then transmitted by thetransmitter 200. The receiver 300 parses each descriptor loop to obtaina linkage descriptor and obtains identification information of a contentitem of an EPG NRT service linked with each content on the basis of thelinkage descriptor. Also, the receiver 300 may provide additionalextended EPG information by launching or playing a specific content itemamong content items corresponding to an NRT service designated as an EPGconsumption model in an NRT-IT on the basis of the obtainedidentification information.

FIG. 146 is a view illustrating a syntax of a linkage descriptoraccording to an embodiment of the present invention.

Referring to FIG. 146, the linkage descriptor may further include anevent_id field or a service_id field or may further include a service_idfield and a content_linkage field.

The target_type field may represent the type of a target content. Forexample, as shown in FIG. 147, a target type field may be displayed tocorrespond to the type of a target content linked with a linkagedescriptor to a field value. The target content may be a TV service(virtual channel), TV event, NRT service or a content item of an NRTservice, and a value corresponding thereto may be one of 0x00 to 0x07.Accordingly, the receiver 300 may determine which type of service thetarget content relates to on the basis of the target type field.

FIG. 147 is a view illustrating a target type field of a linkagedescriptor according to an embodiment of the present invention. As shownin FIG. 147, when the target type field represents a TV event (0x02),the linkage descriptor may include an event_id field according to thetarget type field. When the target type field represents an NRT service(0x03), the linkage descriptor may include a service_id field. When thetarget type field represents a content item of NRT service (0x04), thelinkage descriptor may include a service_id field and a cotent_linkagefield. Accordingly, the receiver 300 first parses the target type field,and determines the type of a target content on the basis of the value ofthe target type field, and also obtains each identifier field accordingto the determined content type so that it may identify the targetcontent.

In addition, according to another embodiment of the present invention,the receiver 300 may include descriptive information of contents (forexample, a virtual channel, an event, or NRT service) to display serviceguide. For this, the receiver 300 may obtain a linkage descriptor fromtables transmitted through a broadcast channel or NRT service signalingchannel.

The linkage descriptor may be included in a channel level descriptorloop corresponding to a specific virtual channel in a VCT. Additionally,the linkage descriptor may be included in an event level descriptor loopcorresponding to a specific event in an EIT instance. Then, the linkagedescriptor may be included in a service level descriptor loop in an SMTcorresponding to a specific NRT service.

The receiver 300 may determine what descriptive information of a virtualchannel, event, or NRT service is included based on the position in aVCT, an EIT, or an SMT including such a linkage descriptor.

Moreover, the receiver 300 may identify at least one content item of anEPG consumption model NRT service linked with the above-mentionedvirtual channel, event, or NRT service on the basis of the linkageinformation in the linkage descriptor. The receiver 300 may provideadditional information on the above-mentioned specific virtual channel,event, or NRT service by launching or playing at least one content item,and the additional information may be displayed on a service guide thata user views.

FIG. 148 is a view illustrating a linkage descriptor according toanother embodiment of the present invention.

The num_of_linked_content_items field may be an 8-bit unsigned integerindicating the number of content items identified in loops starting froma field immediately following this field.

The Service_id_ref field may be a 16-bit unsigned integer matching theservice identifier field of NRT service. The NRT service matched by thisfield is to provide descriptive information for a program or serviceguide, and may be an NRT service designated as an EPG consumption model.The NRT service designated as an EPG consumption model may be includedin a broadcast stream including the linkage descriptor and thentransmitted, or may be transmitted through another broadcast stream inthe same broadcast area.

The content_linkage_ref field may be a 32-bit unsigned integer matchingthe content_linkage field corresponding to a content item of an NRTservice designated as an EPG consumption model that the serviceidentifier reference field in an NRT-IT instance represents.Accordingly, by parsing this field, the receiver 300 may identify acontent item of an EPG consumption model NRT service as a content itemlinked by the linkage descriptor.

The role field may be a 4-bit unsigned integer indicating the role ofthe identified content item. According to the meaning of a valueallocated to the role field, for example, when a value of the role fieldis 0, it represents that the identified content item serves as a previewrole. Additionally, when a value of the role field is 1, it representsthat the identified content item serves a general description role.

Moreover, an EPG provided according to an embodiment of the presentinvention may be provided according to an operation of a DO. However, inthe case of an EPG displaying a portion of a screen, since anapplication needs to be programmed in accordance with the resolution ofa receiver, it may not move in a fixed area. That is, when an EPGservice is played in a receiver or a media player and displayed on ascreen, an operation for bidirectional objects may be required. Forexample, when a caption is additionally displayed on a screen, theposition of an EPG may need to be moved.

Accordingly, according to an embodiment of the present invention, an EPGmay be provided by designating some areas of a screen. Additionally, ifan overlapping area resulting from a contact with another serviceoccurs, the EPG may be moved to a designated another position.

As described above, the EPG may be transmitted through NRT service andmay be executed by an operation of a Declarative Object (DO)corresponding to NRT service. As mentioned above, the DO may betransmitted through a broadcast network or an internet network and theDO may be provided from the receiver 300 at a specific time as adjunctservice for broadcast service. The receiver 300 may need to notify auser that a current content includes adjunct service and also thereceiver 300 may notify a user that providing adjunct service isavailable. A user may recognize that providing adjunct service isavailable and may receive the adjunct service or may maintain currentcontent viewing as it is according to a selection.

Then, according to an embodiment of the present invention, the receiver300 may display an EPG included in such an adjunct service. An EPG DOmay determine the position of a partial area of a screen displaying anEPG on the basis of pre-designated specific position information and theresolution information on the receiver 300. The receiver 300 may displaya position other than a partial area determined in a full screentransparently (as an originally playing screen is).

Then, it may be effective for EPG or adjunct service DO makers to designonly a necessary area. Therefore, according to an embodiment of thepresent invention, adjunct service or EPG makers do not need to createDO in consideration of a full area of a screen but may create a DO onlyfor a specific partial area. Since DO makers do not need to consider anunnecessary area, production time may be reduced and design andprogramming may become easy.

Moreover, a DO operating in a partial screen area may need to move ifnecessary. For example, when a user executes an adjunct service such asa media caption, an EPG may move without interfering with such a basiccaption service.

FIG. 149 is a view illustrating a DO operating in a partial area of ascreen according to an embodiment of the present invention.

As a currently and generally used method, provided is a method ofproviding service in full screen or processing an unnecessary areatransparently in providing an EPG.

However, as shown in FIG. 149, according to an embodiment of the presentinvention, the receiver 300 may provide an adjunct service including anEPG by allocating a designated partial area 400 in an entire screen areadesignated as a Using Area. Additionally, the designated partial area400 may change its position while service is provided.

The receiver 300 may determine the partial area 400 on the basis ofsignalling information on the above-described adjunct service.Additionally, the receiver 300 may allocate the partial area 400 on thebasis of signalling information on the above-described adjunct service.Information on such a partial area, for example, may be included in atrigger and transmitted or may be included in a signalling table andtransmitted.

Accordingly, the receiver 300 may determine when and which area anadjunct service is executed. The adjunct service may include an EPG or acaption service as described above and an area for each execution may bepre-designated as a Safe Area by a service provider. Information on sucha safe area may be included in signalling information or a trigger andtransmitted. The receiver 300 may determine safe areas and partial areaswhere adjunct services are to be displayed on the basis of arelationship between adjunct services operating in the current receiver300.

Then, the receiver 300 may change a partial area in advance where an EPGis to be displayed in correspondence to the execution of another object.Accordingly, the receiver 300 may manage a display area movementschedule between objects by using a table.

Moreover, FIG. 150 is a view illustrating partial areas where an EPG isto be displayed according to an embodiment of the present invention.

As shown in FIG. 150, an area where an EPT is to be displayed accordingto an embodiment of the present invention may be designated as more thantwo areas. For example, more than two safe areas may be designated as anarea of an NRT object corresponding to an EPG. The receiver 300 maydisplay an EPG by selecting one of more than two areas.

Additionally, if a currently displayed EPG is to cover another objectDO, the receiver 300 may move the EPG to another area other than acurrent area among more than two pre-designated areas shown in FIG. 150.For this, the receiver 300 may calculate information on which area in ascreen an NRT service object different from an EPG is to be outputted,in advance, and then may manage it as a table. Accordingly, the receiver300 may make preparation for preventing an EPG and another object frombeing covered by each other.

In such a way, in order for the receiver 300 to change the position ofan object, a broadcast service provider may provide position informationto the receiver 300 so that areas for displaying adjunct services ofcontent do not overlap each other.

Additionally, the receiver 300 may display objects without overlappingby moving the objects to arbitrary screen positions without obtainingposition information.

Then, the receiver 300 may change the size of an object according tobroadcast contents being currently played. For example, the receiver 300may change the size of an EPG according to broadcast contents beingviewed by a user currently. This allows viewers to focus more on animage of a screen and provides service again after an important part ofcontent passes. The receiver 300 may display only simple information tobe small on one side of a screen according to a state of a broadcastimage and display it to be large on a screen by moving more informationafter a predetermined time.

For example, when a broadcasting company broadcasts a drama, if a homeshopping object covers a large portion of a screen, this annoys viewers.Accordingly, in this case, the home shopping object may be displayed tobe small during a time interval in which the drama is broadcasted andafter the drama is ended, the home shopping object may be displayed tobe large.

FIG. 151 is a view when an index is allocated according to the area andsize of an adjunct service object to be displayed.

As shown in FIG. 151, the receiver 300 may set a plurality of positionsand sizes where an adjunct service object such as an EPG and mayallocate an index. The receiver 300 may determine the position and sizeof an object to be displayed by selecting one of preset indicesaccording to a display state.

Moreover, FIG. 152 is a view when an unavailable area of an object isdesignated.

As shown in FIG. 152, the receiver 300 may preset an area where achannel banner is not supposed to be used.

In this case, the receiver 300 may move an object to an area other thana preset usage unavailable area and may display it when an adjunctservice object such as the EPG is executed.

For example, when a caption service is provided from 10:00:00 to10:50:00 and is turned on and operates for 50 min, the receiver 300 maydesignate a caption service area as a usage unavailable area.Additionally, a broadcast service provider may signal usage unavailablearea information to the receiver 300. The receiver 300 may display anadjunct service object such as an EPG on another area in a display areaother than a usage unavailable area.

Additionally, as shown in FIG. 152, when a Channel Banner is displayedon a screen, since another object cannot be displayed on this area, thereceiver 300 may designate the area as a usage unavailable area. Then,before the Channel Banner is displayed, the receiver 300 may move otherobjects displayed on an overlapping position to another position otherthan a usage unavailable area in advance.

A broadcast service transmitting and receiving method according to theabove-mentioned embodiments of the present invention may be implementedby a program executed in a computer and stored in a computer readablerecoding medium. Examples of the computer readable recording mediuminclude read-only memory (ROM), random-access memory (RAM), CD-ROM,magnetic tape, floppy disk, and optical data storage device, and carrierwave (such as data transmission through the Internet).

The computer readable recording medium can also be distributed overnetwork coupled computer systems so that the computer readable code isstored and executed in a distributed fashion. Also, functional programs,codes, and code segments for accomplishing the present invention can beeasily construed by programmers skilled in the art to which the presentinvention pertains.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims.

1-20. (canceled)
 21. An operating method for a broadcast receivingdevice, comprising: receiving an audio or video, wherein the audio orvideo is included in a broadcast stream which is not transmitted throughan internet protocol (IP) network; receiving an address of a signalingserver; and transmitting a request message for a signaling table to thesignaling server; receiving the signaling table based on the requestmessage through the IP network, wherein the request message include afirst query information which includes time information of the requestmessage, and a second query information which designates the signalingtable.
 22. The method of claim 21, wherein the first query informationincludes an update flag which indicates whether the request message isfor update.
 23. The method of claim 21, wherein the first queryinformation includes a duration of the time interval for the requestmessage.
 24. The method of claim 21, wherein the first query informationincludes a start time of the time interval for the request message. 25.The method of claim 21, wherein the first query information usesfollowing query terms, start=<start_time>[&duration=<duration>][&update], wherein start_time represents a start time of the timeinterval for the request message, duration represents a duration of thetime interval for the request message, update represents an update flagwhich indicates whether the request message is for update.
 26. Themethod of claim 21, wherein the second query information includes atleast one of a channel identifier, a service identifier, and a signalingtable identifier, wherein the channel identifier represents a channelnumber of a virtual channel for which the signaling table is requested,wherein the service identifier represents a service identifier of a NRTservice for which the signaling table is requested, wherein thesignaling table identifier represents a identifier identifying thesignaling table.
 27. The method of claim 26, wherein the signaling tableidentifier represent at least one of PSIP set, basic NRT set, extendedNRT set, VCT, EIT, ETT, SMT, NRT-IT, TFT, PIT and PTCT.
 28. The methodof claim 27, wherein the PSIP set includes TVCT, EIT, and ETT for avirtual channels in the broadcast stream, wherein the basic NRT setincludes SMT, NRT-IT and TFT for a NRT service in the broadcast stream,wherein the extended NRT set includes basic NRT set, PIT and PTCT for aNRT services in the broadcast stream.
 29. The method of claim 21,wherein the audio or video is uncompressed, wherein receiving theaddress of the signaling server comprises: receiving the address of thesignaling server based on the audio or video.
 30. The method of claim29, wherein receiving the address of the signaling server based on theaudio or video comprises: extracting a signature from frames of theaudio or video and receiving the address of the signaling server basedon the signature.
 31. A broadcast receiving device, comprising: areceiver for receiving an audio or video, wherein the audio or video isincluded in a broadcast stream which is not transmitted through aninternet protocol (IP) network; and a service manager for receiving anaddress of a signaling server, and transmitting a request message for asignaling table to the signaling server, and receiving the signalingtable based on the request message through the IP network, wherein therequest message include a first query information which includes timeinformation of the request message, and a second query information whichdesignates the signaling table.
 32. The device of claim 31, wherein thefirst query information includes an update flag which indicates whetherthe request message is for update.
 33. The device of claim 31, whereinthe first query information includes a duration of the time interval forthe request message.
 34. The device of claim 31, wherein the first queryinformation includes a start time of the time interval for the requestmessage.
 35. The device of claim 31, wherein the first query informationuses following query terms, start=<start_time>[&duration=<duration>][&update], where start_time represents a start time of the time intervalfor the request message, duration represents a duration of the timeinterval for the request message, update represents an update flag whichindicates whether the request message is for update.
 36. The device ofclaim 31, wherein the second query information includes at least one ofa channel identifier, a service identifier, and a signaling tableidentifier, wherein the channel identifier represents a channel numberof a virtual channel for which the signaling table is request, whereinthe service identifier represents a service identifier of a NRT servicefor which the signaling table is request, wherein the signaling tableidentifier represents a identifier identifying the signaling table. 37.The device of claim 36, wherein the signaling table identifier representat least one of PSIP set, basic NRT set, extended NRT set, VCT, EIT,ETT, SMT, NRT-IT, TFT, PIT and PTCT.
 38. The device of claim 37, whereinthe PSIP set includes TVCT, EIT, and ETT for a virtual channels in thebroadcast stream, wherein the basic NRT set includes SMT, NRT-IT and TFTfor a NRT service in the broadcast stream, wherein the extended NRT setincludes the basic NRT set, PIT and PTCT for a NRT services in thebroadcast stream.
 39. The device of claim 31, wherein the audio or videois uncompressed, wherein the service manager receives the address of thesignaling server based on the audio or video.
 40. The device of claim39, wherein the service manager extracts a signature from frames of theaudio or video, and receives the address of the signaling server basedon the signature.